Abstract：Historical data of landslide and rainfall of 577 landslides in several decades are analyzed and the hydrogeology conditions in Chongqing area are introduced in detail. The relationship between rainfall and landslide is investigated in respects of time distribution，intraday rainfall，rainstorm，comparison of time between landslides and rainfall，and comparison between the days with rainfall and those with continuous rainfall within ten days before the landslide；and several conclusions are drawn which prove that the relationship between rainfall and landslide is close. The quantity of landslide has direct ratio with rainfall. Landslide usually occurs within four days after a rainfall and within one day after a rainstorm. On the assumption that rainfall begins to infiltrate into soil when rainfall is 3 mm，if there is 3-day continuous rainfall，the possibility of landslide is very high.
