Abstract: Refined measurement of the groundwater response to external factors is of great significance to the analysis of landslide stability. Considering that the stability of the reservoir landslide is affected by the reservoir water level and rainfall, based on the association rule mining method, the research method for revealing the response rules of the underground water suffered rainfall and periodic water level is proposed, taking the Madiwan landslide in the Three Gorges Reservoir area as an example. First, the groundwater response lag period is determined through characteristic period analysis and Granger test, and then the influencing factors of groundwater are determined based on the response lag period. Finally, the groundwater response characteristics of the Madiwan landslide are revealed through the Apriori data mining algorithm. The research results show that the groundwater response at the front edge of the landslide has a greater correlation with the fluctuation of the reservoir water level, and the groundwater response at the middle and rear edge of the landslide has a greater correlation with rainfall. The best response lag period of the groundwater of the Madiwan landslide to rainfall and reservoir water is 1 day. The underground water level in the later part of landslide is sensitive to the rainfall, while that in the former part of the landslide is constantly related to the water level.