Abstract: Based on the observational data of 0–200cm soil moisture before winter wheat sowing from 1991 to 1996 in Zhengzhou, the vertical distribution of soil moisture before sowing is simulated by using cubic polynomials. The results show that soil moisture would increase with the depth of soil layer. There is a good correlation between 0–50 cm soil moisture and 0–200 cm soil moisture before sowing, the significance level of which reaches 0.01, therefore the 0–200 cm soil moisture before sowing could be estimated from the 0–50 cm soil moisture.