Abstract: Alpine grassland is a widely distributed vegetation type across the Qinghai-Tibet plateau. In this paper, we studied the influencing factors of topsoil labile organic carbon in alpine grassland ecosystem on the southeast slope of Mountain Nyenquentanglha via field investigation and laboratory analysis. Based on the study, average topsoil (0～20 cm) labile organic carbon content in the alpine grassland ecosystem on the studied area is 2.61 ±0.31 g·kg^-1. The main factors influencing distribution of soil labile organic carbon are altitude and slope gradient (terrain factor), underground soil biomass in the 0～10 cm and 10～20 cm depths (vegetation factor), soil moisture of the 0～10 cm and 10～20 cm depths and soil bulk density of 0～20 cm depth (physical factor), and soil total K content (chemical factor). Soil moisture and bulk density present most significant influence. The distribution characteristics of topsoil labile organic carbon content is in increase-decrease-increase-decrease tendency with altitude in the range of 4 421～4 598 m.