Based on the observed data of monthly temperature, monthly rainfall of 34 weather stations and ten-day soil humidity of typical maize agro-meteorological stations during growth period in Jilin Province from 1981 to 2010, using statistical method, the changing characters of temperature and rainfall and relationship between soil hu-midity of corn farmland and climate were analyzed. The results were as follows: since 1981, the temperature was in-creasing, the rainfall was decreasing, the soil humidity was descending during growth period, and temperature wasincreasing in each region, rainfall was decreasing in middle region, soil humidity descending in middle and middle-east region was a sudden phenomenon, which occurred in 1990 s. The relation between soil humidity and rainfall wasclosely in each region, the relation between soil humidity and temperature was closely in the middle and west region.Temperature increasing and rainfall decreasing were the main climatic factors caused soil humidity descending.