The released carbon and nutrients from soil as affected by freeze-thaw cycle are important guarantees for maintaining winter soil microbial activity in subalpine forests. In order to understand the effects of freeze-thaw cycles on the structure of soil microbial community, soils in a coniferous (Abies faxoniana) forest, broadleaf (Betula albosinensis) forest and mixed forest in subalpine forests of western Sichuan were taken as study objects. The short-term response of the phospholipid fatty acid (PLFAs) contents and structure of microbial communities to freeze-thaw cycle was studied in microcosms. A total of eighty times of freeze-thaw cycle were performed to the microcosms, with which a freeze-thaw cycle was treated as the soil being in below 5 ℃ for 12 h and followed being in above 5 ℃ for 12 h. The results showed that the response of soil microbial communities to freeze-thaw cycles varied with forest type. Compared to the five times of freeze-thaw cycle, the abundances of the bacteria, fungi, gram-positive bacteria (G~+) and gram-negative bacteria (G~-) PLFA were reduced in all forest soil after the eighty times of freeze-thaw cycle; the bacterial PLFA abundances of the mixed, coniferous and broadleaf forests were reduced by 71.9%, 73.7% and 74.6%, respectively; the corresponding decreases in the fungal PLFA abundances were 55.5%, 75.4% and 84.7%, the G~+ PLFA abundances were 77.1%, 68.8% and 73.7% and the G~- PLFA abundances were 70.6%, 78.1% and 78.8%, respectively. Freeze-thaw cycle significantly affected the fungi/bacteria ratio of the broadleaf forest, while forest type had no significant effect on the ratio of fungi/bacteria and G~+/G~-. Both the Shannon-wiener diversity index and Pielou evenness index were significantly affected by the freeze-thaw cycle, and the Shannon-wiener diversity index and Pielou evenness index increased with the increase of freeze-thaw cycle in the mixed forest, but which decreased in the coniferous forest and broadleaf forest as the freeze-thaw cycle proceeded. The redundancy analysis (RDA) suggested that soil nutrient availability was significantly correlated with the microbial biomass and community structure during the study period. These results indicate that changes in the freeze-thaw cycle patterns during the winter period as affected by global warming can influence soil microbial biomass and diversity in subalpine forests by altering soil nutrient availability.