In order to explore the variation trend of soil microbial biomass carbon (MBC) and nitrogen (MBN) along an elevation gradient and their main controlling factors in a mountain forest region in Shennongjia Natural Reserve, China, MBC and MBN at 0-10 cm soil layer were measured and their relationships with environmental factors were analyzed in four typical forest types in late August of 2011. The results showed that the values of MBC and MBN were in order of alpine shrub > subalpine coniferous forest > coniferous and broadleaf mixed forest > deciduous broadleaved forest. MBC and MBN significantly increased with the elevation (P<0.05), in consistent with the trend of soil organic carbon and total nitrogen. However, soil microbial quotient (q_MB) decreased first and then increased with the elevation. Pearson’s correlation analysis showed that MBC and MBN were significantly positively correlated (P<0.05) with soil organic carbon and total nitrogen, but negatively with soil moisture, soil temperature and soil pH (P<0.05). Therefore, soil moisture, soil temperature, soil pH, soil organic carbon and soil total nitrogen might be the important factors influencing the variations of soil microbial biomass along the elevation gradient in Shennongjia Mountain.