Over a three-year period the authors observed a devastated small forest watershed in JiangXi Province in southern China, to estimate rainfall, runoff and sediment yield. The observed watershed is in a hilly mountainous area, overlying weathered granite, and has many bare slopes and devastated forests. The devastation has increased due to indiscriminate cutting of trees, mowing of ground-cover, and raking up of fallen leaves for fuel. Precipitation in this area is concentrated in the summer rainy season from June to August. The authors analysed observed data primarily of rainfall, runoff and sediment yield. From the observations, it was noticed that there are two peaks of sediment discharge, one occurring in spring from April to May, and the other in the latter half of August. The earlier peak of sediment discharge is considered to be due to freezing and thawing, and the latter due to raindrop impact. The observed results were compared with data obtained from the experimental watersheds of the central part of Japan, and it was found that the sediment discharge rate observed in China is smaller than that of Japan. While their annual precipitation is nearly the same, and their geological conditions similar, their climate is quite different. In winter, the observed area of China has only 20-30 freezing days, whereas the comparable area in Japan has 60-100 days with a temperature below 0 degrees C.