Under the persistent rise in global average temperatures, extreme weather events have become increasingly frequent, posing severe challenges to the natural environment and human activities. As a critical climatic element, precipitation variations profoundly impact ecosystem balance, water resource management, and socio-economic development. This study analyzed daily precipitation data from 2,217 rainfall stations across China (1973–2023) using the Mann–Kendall (MK) trend test, validated by the sliding average method and climate tendency rate method. Key findings include: (1) Annual maximum 1-day, 3-day, and 5-day cumulative precipitation trended upward in multiple river basins. (2) Torrential rain frequency and intensity increased widely; heavy torrential rain showed complex trends in eastern regions (rising and declining stations intertwined); extreme torrential rain remained generally stable, though eastern coastal areas need heightened vigilance. (3) Annual precipitation had intricate regional features: most areas trended downward, while northern regions and the lower Yangtze River basin trended upward. (4) The MK test, moving average method, and climate tendency rate method reached consistent conclusions, and the multi-method approach comprehensively reveals precipitation’s spatiotemporal variations.