This paper takes 10 times of obvious long-term continuous rise of water level in Bengbu Monitoring Center well from 2017 to 2020 as the research object. Multiple regression analysis was conducted on influencing factors of rainfall in different periods before and after 10 times of water level rise. Multiple regression equations were established. The results show that: the 10 times of obvious long-term sustained rise of water level from 2017 to 2020 are mainly related to the influence of rainfall during the rise. It has no significant relationship with other rainfall parameters. Combined with the analysis results of earthquake catalogs above ML2.5 in Bengbu area, the law of water level rising continuously for a long time corresponds to the law of earthquake frequency, which shows that rainfall and regional stress field change jointly affect the water level change of Bengbu Monitoring Center.