Whether the rainfall runoff mechanism has significant difference in different stages is an urgent problem to be solved in practice. In this paper, the consistency of rainfall-runoff series is analysed concerning the hydrologic data of four reservoirs in Hebei Province, Haihe river basin as the foundation. Through the double mass curve of rainfall- runoff relation, the change process of annual runoff coefficient and the rank sum test method, the paper selected incoming runoff hydrological series consistency of the four reservoirs from 1980to 2008to research. The results show that incoming runoff hydrological series of AGZ, GN,HBZ reservoir from 1980to 2008has consistency, though the annual runoff, runoff coefficient were different, but the relation of rainfall and runoff has no significant differences. WK reservoir incoming runoff hydrological series are inconsistent, Rainfall runoff mechanism has changed. It is necessary to analyze the underlying surface change and modify natural runoff data.