Abstract:Soil microbial biomass carbon is an important component in carbon cycle of the terrestrial ecosystem. We chose Evergreen Broadleaf Forest (EBF), Coniferous Forest (CF), Dwarf Forest (DF) and Alpine Meadow (AM) as experimental sites along an elevation gradient in the national natural preserve of Wuyi Mountains, and to examine the variations of soil microbial biomass and its influencing factors from June, 2005 to April, 2006. The results showed that: (1)At 0-10cm depth of soil layer, the annual mean value of soil microbial biomass was increasing with increasing elevation. The soil microbial biomass of AM was 4.07 g?kg-1, and which was 2.06, 3.21 and 3.91 times higher than that of DF, CF and EBF, respectively (p<0.01), and the annual mean value of soil microbial biomass of DF was significantly higher than that of EBF, CF, respectively (p<0.05). However, the annual mean values of soil microbial biomass between DF and CF were not significantly different (p>0.05). Variations of soil microbial biomass at 10-25cm depth of soil layer was the same as that at 0-10cm depth of soil layer. (2)At 0-10cm soil layer, the annual mean values of soil microbial biomass were significantly correlated to soil organic carbon, total nitrogen, total sulphur and soil moisture, respectively. At 10-25cm depth of soil layer, the annual mean values of soil microbial biomass were significantly correlated to soil organic carbon, total nitrogen, respectively. Our research showed that soil microbial biomass were increasing along the elevation gradient in subtropical forest in Wuyi Mountain, and soil organic carbon, total nitrogen, total sulfur or soil moisture might be the major factors controlling soil microbial biomass.