Abstract: The Baijiabao landslide is a representative of landslides with hysteretic"step-type" deformation. According to qualitative analysis, the reservoir water level decline is the main influencing factor of Baijiabao landslide deformation, and its impact degree is greater than rainfall. In order to clarify the response degree of Baijiabao landslide deformation to reservoir water level fluctuation and rainfall, this paper divides it into five stages according to the annual fluctuation of reservoir water level. The Pearson correlation coefficient method is used to quantitatively calculate the correlation on deformation of Baijiabao landslide between water level and rainfall. The calculation results show that the deformation of each monitoring point and the reservoir water level and rainfall are the most relevant in the comprehensive calculation from May to June. The absolute correlation coefficient between deformation and reservoir water level is about 0.75, and is greater than the maximum correlation coefficient between deformation and rainfall(about 0.45). In order to completely eliminate the interaction between reservoir water level and rainfall, the Pearson correlation coefficient is used to calculate the net correlation coefficient between Baijiabao landslide deformation and reservoir water level and rainfall. Finally, the net correlation coefficients are used to compare with the daily deformation displacement of the GPS automatic monitoring point in 2017-2018 to verify. The results show that the response of the deformation of the Baijiabao landslide to the reservoir water level is greater than to the rainfall. The response degree is the highest in the rapid decline of the reservoir water level, and it is consistent with the monitoring results of the newly built GPS automatic monitoring points, the results of qualitative analysis and Pearson correlation coefficient analysis. This study can provide a scientific basis for the quantitative analysis of the factors affecting landslide deformation.