The response of respiration rates of root, Ao layer and mineral soil to varying environmental factors was studied in Popuius maximowiczii stand (25-year-old) during the growing season of 1997. Soil temperature showed a pronounced seasonal course, in contrast to soil moisture. The mineral soil respiration was high in August, and root and Ao layer respiration, were high in July. An exponential equation best described the relationships between soil temperature and mineral soil respiration, and total soil respiration (r＝0.95 and 0.92, p＜0.001), respectively. In P. maximowiczii stand, soil respiration rates were reduced by about 19% after removal of the Ao layer, and by about 30% after removal of living root. Therefore, mineral soil respiration seemed to contribute gretly to the total soil respiration (50%).