In order to study on energy exchange between the ground surface and the lower atmosphere, the effects of the soil moisture on energy balance components at the ground surface were observed. The field observations were carried out at the Environmental Research Center of the University of Tsukuba in August and September, 1982. The results can be summarized as follows. 1. Increase in the volumetric soil water content from 22% to 44% due to precipitation results a decrement in albedo from 0.14 to 0.09. The relation between the soil water content and albedo reveals a step-like variation at critical point of soil water content of 26%_??_29%. 2. The step-like variation indicates a positive relationship between the incoming solar radiation flux net radiation flux ratio (Rn/I) and the soil water content. The ratio of Rn-G and incoming solar radiation flux also reveals a step-like variation in a positive re lationship with the soil water content. 3. Higher significance levels in correlation coefficients were found between net radia tion flux and incoming solar radiation flux, and also between soil heat flux and net radia tion flux in the two groups through the soil water content. 4. G/Rn ratio is proportional to soil water content during nighttime, while it shows rather poor negative relationship during daytime.