In the light of characteristics of North China Plain such as hydrogeological conditions, high degree utilization of groundwater, remarkable differences in buried depth of groundwater, aerated zone and on the basis of large quantities of drilling and groundwater level monitoring data, we divided the North China Plain into four hydrogeological units, considering the depth of 7 meters as the precipitation infiltration boundaries and endowed drilling strata with infiltration coefficient according to the hydrogeological conditions of partitions, and obtained the precipitation infiltration coefficient distribution in the 1960s, 1980s and 2000s using weighted average method. The results indicate that the precipitation infiltration coefficient tends  to increase with the decline of groundwater level. Although precipitation has a decrease tendency in nearly 50 years, the precipitation infiltration increased due to the infiltration coefficient. The precipitation infiltration amount were 118.86×10⁸, 147.91×10⁸, 174.33×10⁸ m³  in the 1960s, 1980s and 2000s.