Abstract: Objective To separate and quantify the total, autotrophic and heterotrophic soil respiration. Method By the method of infrared gas exchange analyzer in trenching-plot, the total soil respiration (RS), autotrophic (RA) and heterotrophic respiration (RH) in a Quercus variabilis plantation were investigated in hilly area of Xiaolangdi Reservoir of Yellow River. The seasonal dynamics contribution rate and the environmental factors of RS, RA, and RH were determined. Result The results showed that the RS, RA and RH varied with the season, the maximum and the minimum were observed at summer and winter, respectively. Significant exponential relationships were obtained between RS, RA and RH and soil temperature at 5 cm (PRA, RH, and Rs, (Q10) were calculated as 3.40, 2.90 and 2.45 respectively. The RS, RA and RH were significantly lined with soil volumetric water content at 0~10 cm (PRs and RA had a linear correlation with soil pore water conductivity at 0~10 cm (PQ10 of Rs and RH had the highest value in summer and the lowest in winter. Compared with Q10 in Rs and RH, the seasonal variation in Q10 of RA presented opposite trend. The estimated contributions of RA and RH on Rs were 13.23%~37.33% and 62.67%~86.76%, respectively. The contribution of RA on Rs was consistent with soil temperature seasonally. In this study, the annual CO2 flux of Rs, RH and RA in the Q. variabilis plantation were 1 616.41, 1 199.39 and 417.02 g·m-2·a-1, respectively. Conclusion As the main component of total soil respiration, the heterotrophic respiration was significantly correlated with environmental factors, which could influence the overall emission from soil surface and provide theoretical support for further research about carbon cycle and energy exchange in forest ecosystems.