D4 is a novel Chinese dialogue dataset for depression diagnosis chat. It is a new type of dialogue called task-based chat. The dataset consists of 1,339 multi-turn (Avg. turns 21.6) dialogues, including dialogue summaries and diagnosis results. This dataset is mainly used to build a more empathy-driven and diagnostically accurate consulting dialogue system. To prevent privacy violations or other potential misuse, the dataset is available at https://x-lance.github.io/D4/ Apply for download and use.