The water regime in cultivated black soils are not only influenced by the climatic factors, but also by the crops. In the black soils under different crops, there were obvious difference in the levels of soil humidity and the residual water in soils after harvest of crops. In wheat fields, an high evapotranspiration intensity with a peak which happened earlier and a maximum annual rate of evapotranspiration were found. But in fields of intertilled crops such as soybean and corn, the evapotranspiration intensity was, lower, the evapotranspiration peak came later and the annual rate of evapotranspiration was smaller. In the same year, soll humidity in wheat fields was lower than that in soybean and corn fields, and the residual soil water in wheat field after harvest was the smallest.