A consensus in global ecology is that climate change is profoundly altering the process of terrestrial ecosystem. In particular,more and more attentions have been focused on the effects of snow pack on soil process in cold biomes recently, since climate change characterized by winter warming and extreme is changing the pattern of seasonal snow cover and freezethaw cycles in the high-latitude and high-altitute regions. As yet,the results concerning the effects of seasonal cover and freeze-thaw cycles on soil process remain uncertainty,and little information has been available on the effects of snow pack on soil nitrogen tansformation in the subalpine forest of western Sichuan,China. In order to deeply understand the process of soil nitrogen transformation in the subalpine forest of western Sichuan under climate change scenarios,therefore, wintertime net nitrogen mineralization,net nitrogen ammonification,net nitrogen nitrification and microbial nitrogen immobilization in soils under three depths of snowpacks (deep snowpack,middle snowpack and shallow snowpack) were measured in two subalpine forests of western Sichuan,which locates at the upper reaches of Yangtze River and the eastern Qinghai-Tibet Plateau. The top of soil columns sampled from Abies faxoniana + Betula albo-sinensis mixed forest and secondary fir forest were closed,and then in-situ incubated in the forest floor under deep snowpack,middle snowpack and shallow snowpack of the corresponding forest from November 2011 to April 2012,respectively. The results indicated that wintertime soil net nitrogen ammonification ranged from -2. 37mg /kg to -2. 22 mg /kg under different snowpacks in the mixed forest,and from -7. 73 mg /kg to -7. 10 mg /kg under different snowpacks in the secondary fir forest. Wintertime soil net nitrogen nitrification varied from 71. 98 mg /kg to 82. 69 mg /kg under different snowpacks in the mixed forest,and from 101. 56 mg /kg to 124. 89 mg /kg under different snowpacks in the secondary fir forest. Net nitrogen nitrification was significantly (P < 0. 05) higher than net nitrogen ammonification. The highest rates of soil nitrogen ammonification, nitrification,mineralization and microbial nitrogen immobilization were observed in the middle snow pack,but no significant (P> 0. 05) differences were observed among snow packs. Meanwhile,all measured indexes in each snow pack were significantly (P<0. 05) higher in the secondary fir forest than those in the fir-birch mixed forest. However,the interaction of snow pack and forest type was not significant on wintertime soil nitrogen transformation. The results suggested that soil nitrogen nitrification be a major process of wintertime soil nitrogen mineralization,and the process of soil nitrogen nitrification and ammonification be regulated by different microbial communities in the subalpine forests of western Sichuan, China. The result also implies that the decline of snowpack caused by climate change,in the short-run,has little effects on soil nitrogen mineralization in our study area.