The relations between soil moisture and precipitation at seasonal to interannual scales are investigated with observed precipitation and in-situ soil moisture measurements from China (43 stations), Mongolia (42 stations) and Russia (130 stations). Analysis of data averaged over the entire growing season indicates that soil moisture and precipitation show strong consistency in the interannual variations, and precipitation is a dominant factor to control soil moisture variations over an interannual scale. The growing season is characterized by different vegetation activities, thus influences of vegetation types on soil moisture variations are also investigated at an interannual scale. Soil moisture memory is further investigated by analyzing the correlation between soil moisture and precipitation on seasonal scale. The results from Russian data show that soil can remember the moisture in spring to enhance the precipitation during summer, and also can remember the precipitation over previous autumn and winter seasons into its spring soil moisture bank. Soil moisture memory in Mongolia is weak, and there is no memory found in China. Preliminary study on the mechanism of soil moisture memory suggests that the vegetation and winter freezing temperature are critical for soil moisture memory bank buildup and release. Surface soil moisture retrieved from the C-band radiometer on the Scanning Multifrequency Microwave Radiometer (SMMR) instrument is compared with in-situ measurements to detect the sources of discrepancies and assess the limitations and importance for data assimilation techniques in retrieving the root zone soil moisture.