Future precipitation change is anticipated to have a profound influence on ecosystem carbon (C) cycling, especially soil respiration, the largest C flux from the terrestrial ecosystem to the atmosphere. Due to different substrate sources and biological processes, the heterotrophic (SR_h) and autotrophic (SR_a) components of soil respiration (SR_tot) may respond to changing precipitation in different ways. Determining the differential responses of SR_h and SR_a to precipitation will facilitate our evaluation of soil C storage and stability under future precipitation change. Here, a 3-year precipitation manipulation experiment with 5 levels of precipitation (±60%, ±30% and ambient growing season precipitation) was conducted in a semiarid steppe to determine the influence of precipitation on soil respiration. Results showed that SR_tot increased nonlinearly with increasing water supply, in which, SR_h increased much more than SR_a. Consequently, the ratio of SR_h to SR_tot was enhanced significantly with increasing precipitation, i.e., from 41% to 62% as precipitation increased from 122 mm to 408 mm. Structural equation modeling analysis indicated that changes in SR_hand SR_a were predominated by the soil water content (SWC) and plant growth, respectively. The stronger effects exerted by changes in precipitation on SWC compared with plant growth contributed to the greater change in SR_h than in SR_a. Additionally, SR_a exhibited a higher temperature sensitivity than SR_h. Thus, the increased soil temperature in the drought treatments had greater influence on SR_athan SR_h, and greatly offset the influence of drought stress on SR_a, leading to the smaller change in SR_a compared with SR_h. Our study highlights the different responses of the two soil respiration components to changing precipitation. These results indicate that future increases in precipitation in semiarid regions will increase soil heterotrophic respiration which may accelerate the turnover of soil C, and further affect the stability of soil C stock.