**Abstract: Big Data Research Boosts Positive Psychology in China - Tsinghua University** From February 8 to 10, Professor Kai-Ping Peng, the head of the Department of Psychology at Tsinghua University, was invited to attend the 4th Australian Positive Psychology and Well-Being Science Conference. As a distinguished guest, Professor Peng delivered a keynote speech titled "Positive Psychology in China," highlighting the research conducted by the Behavior and Big Data Lab at Tsinghua University under his leadership. The presentation also emphasized the role of positive psychology in China's development and the contributions of Tsinghua University's psychology department. **Key Psychological Trends Over 200 Years** Professor Peng's research team utilized Google Books' word frequency statistics over the past 200 years to identify significant trends in human psychology. They found that since the early 18th century, two crucial psychological dimensions have been on a decline: life goals, faith, and meaning, as well as positive emotions. The team attributed these declines to the rising trends of utilitarianism, materialism, and individualism in human society. These shifts in belief systems have eroded the sense of meaning and reduced positive emotional experiences, leading to a decrease in overall happiness. The intensification of these trends is linked to changes in economic production methods, lifestyles, and the process of modernization. **Urbanization and Mental Health** Similar to the United States in the 1920s, where urbanization led to a balance between urban and rural populations, China's rapid urbanization has brought both convenience and significant challenges. These challenges mirror the social and cultural issues faced by Americans in the early 20th century, resulting in increased anxiety and depression. The concept of the "American Dream," coined by historian James Adams in "The Epic of America," reflects the societal changes and psychological impacts of that era. In 2013, Chinese President Xi Jinping introduced the "Chinese Dream," which, like the "American Dream," represents the highest psychological needs of the people and serves as a spiritual pillar for social progress. Professor Peng highlighted the importance of positive psychology in China, driven by historical necessity, developmental requirements, and the aspirations of the Chinese people. **Development of a Chinese Psychological Lexicon for Happiness** Professor Peng's team at Tsinghua University, in collaboration with Professor Martin Seligman's team from the University of Pennsylvania, developed a Chinese psychological lexicon to measure happiness. This lexicon includes traditional dimensions such as positive emotions, meaning, engagement, relationships, and achievement, but uniquely adds a dimension related to events. This addition reflects the Chinese tendency to express happiness through actions rather than words, a finding based on extensive research on Chinese happiness events. The lexicon also considers the prevalence of emojis on social media as a means of expressing happiness. **Chinese Happiness Map** Using this lexicon, the team analyzed all data from Sina Weibo (a popular Chinese microblogging platform) for the year 2013. They created a "Chinese Happiness Map" by scanning the happiness lexicon among Weibo users in different regions. The map revealed that the relationship between happiness and GDP is not linear. In poorer areas, happiness increases with economic development, but once a certain level of economic prosperity is achieved, further economic growth does not significantly boost happiness. **Temporal Effects of Happiness on Social Media** Another intriguing study by Professor Peng's team examined the temporal effects of happiness on social media. By analyzing Sina Weibo data throughout 2013, they observed that significant negative events, such as the Changchun car theft and infant murder case on March 5, the Boston Marathon bombing on April 16, and the Ya'an earthquake on April 20, caused noticeable drops in the happiness index. Conversely, positive events, like the Guangzhou Evergrande football team's championship win on November 10, led to spikes in happiness. The Ya'an earthquake, for instance, led to a decrease in positive emotions but a peak in the dimensions of relationships and meaning, demonstrating a large-scale psychological synchronization effect for the first time. **Psychological Impact of Holidays** The team also explored the psychological impact of holidays on social media. Contrary to common intuition, holidays do not always bring happiness simply because they are days off. Traditional holidays such as the Spring Festival and Mid-Autumn Festival, which have deep historical and psychological roots, tend to bring more joy than modern holidays like New Year's Day and National Day. Non-official holidays with strong psychological significance, such as Valentine's Day and Thanksgiving, also showed high peaks in happiness, despite not being official days off. Holidays like Labor Day, which lack deep psychological meaning, had less impact on happiness even though they are days off. The data from the study confirmed that Saturday is the happiest day of the week for Chinese people, with the highest positive emotions and lowest negative emotions. **Significance of Big Data in Positive Psychology** Professor Peng discussed the importance of using big data to study positive psychological concepts like happiness, morality, culture, and innovation. His team's work at the Behavior and Big Data Lab at Tsinghua University has shown that these fundamental human issues can be scientifically analyzed using big data methods. This approach not only provides valuable insights into psychological trends but also helps in understanding the complex interplay between societal changes and individual well-being. The presentation by Professor Peng was met with widespread interest and high praise from conference attendees, underscoring the significance of his research and the potential of big data in advancing the field of positive psychology in China and globally.