Abstract: Influenced by climate change,human activities,and other factors,the Haihe River Basin （HRB） is one of the regions with the most severe water resources decline in China.To study the influencing factors of the evolution of water resources in the HRB,taking into account the changes in precipitation intensity levels within the year,based on meteorological observation data,the third water resources assessment and water resources bulletin in the HRB,this paper uses the linear slope,M-K trend test,and t-test to analyze the variation in the total amount of water resources,different levels of precipitation,and potential evapotranspiration in the HRB from 1956 to 2019.The M-K mutation test is used to analyze the abrupt change time of the total water resources in the HRB,and the partial least squares regression is used to analyze the quantitative contributions of meteorological factors and underlying surface changes on the variations in the total water resources before and after the abrupt change.The results show that:（1） The total amount of water resources in the HRB decreased significantly at a rate of 3.048 billion m~3/10 a,and an abrupt change occurred in 1980.Before and after the abrupt change,the total water resources decreased from 41.09 billion m~3 to 29.90 billion m~3.（2） Before and after the mutation,light rain,moderate rain,heavy rain,torrential rain,and potential evapotranspiration decreased by 8.34,6.69,12.96,21.17,and 19.1 mm,respectively.Among them,light rain,moderate rain,heavy rain,and potential evapotranspiration decreased non-significantly,but torrential rain decreased significantly.（3） Among the 11.19 billion m~3of the decline in total water resources,the contributions of light rain,moderate rain,heavy rain,heavy rain,potential evapotranspiration,and underlying surface were-800 million m~3 （7%）,-520 million m~3 （5%）,-1.60 billion m~3 （14%）,-3.47 billion m~3 （30%）,120 million m~3 （1%） and-4.91 billion m~3 （43%）,respectively.The reduction of torrential rainfall and the underlying surface changes were the main factors for the decrease in water resources in the HRB.The study serves as a scientific basis for formulating sustainable water resources development and utilization plan in the HRB.