Abstract: Soil moisture is an important factor associated with the crop growth and development. In this paper, the seasonal changes of soil moisture were analyzed based on the observation data on soil moisture collected in the national agrometeorological station of Tongliao in the recent ten years. The results showed that an obvious jump change was observed in annual and seasonal soil moisture in Tongliao in the recent ten years, with the best situation from 2012 to 2013 and the worst in 2009. Furthermore, there were obvious differences in the seasonal distribution of soil moisture, which was higher in summer and lower in spring and autumn.