Experimental studies were conducted to make clear the soil moisture environment under the condition of paddy-upland rotational fields by investigating water-table depths and soil moisture contents during growing season of crops in two kinds of soil. The following results were obtained. 1. Although water-table depths fluctuated with the amount of rainfall in the experimental field, it seemed that the variation of vater4able depths in the paddy-upland rotational, field was strongly affected by the condition of locations on paddy fields. 2. It is recognized that the concept of sum of excess water depth(SEW_xx) and sum of excess water day(SED_xx) can be used to represent the soil moisture stress index due to the fluctuation of water-table depths. 3. The results of this study clearly indicate that drainage in paddy-upland rotational field to maintain an optimum soil moisture content must be made by introducing the concept of block drainage which needs both subsurface drainage and intercept drainage around a field. 4. Soil moisture contents were affected by both the amount of rainfall and water-table depths, however, the moisture content for top soil showed higher correlation with the amount of rainfall while that for subsoil with water-table depths.