Not only do soil enzymes take part in carbon and nutrient cycles in soil ecosystems, but act as the sensitive bioindicators in indicating environmental changes. Consequently, climate change characterized by climate warming and seasonal snow cover decline might give to a certain extent effects on soil enzyme activity in high-altitude and high-latitude regions, and thereafter change the cycles of carbon and nutrients in soil ecosystems in cold biomes. However, the response of soil enzyme activity to climate warming at different critical periods remains unknown. In order to understand the effects of climate warming on soil ecological process in the alpine forest in western Sichuan, soil columns sampled from a primary Minjiang fir (Abies faxoniana) forest at 3582 m elevation was therefore in-situ incubated in the primary coniferous forest, transplanted and incubated in 3298 m and 3023 m sites in May 2010, respectively. Theoretically, the temperatures of soil and atmosphere would increase by 1.78℃ and 3.52℃, respectively. Based on the previous studies and simultaneous temperature monitoring, soil columns at three elevations were respectively retrieved at the early growing period (EGS), later growing period (LGS), onset of soil freezing period (OF), deeply frozen period (DF) and thawing period (TP) from August 2010 to April 2011, and the activities of invertase related to carbon cycle and urease related to nitrogen cycle in both soil organic layer (OL) and mineral soil layer (MS) were instantly measured in the lab. Different from the theoretical prediction values, annual mean air temperatures at 3298 m and 3023 m elevations were actually higher 1.39℃ and 2.64℃ than that at 3582 m elevation, respectively. As affected by seasonal snow cover, lowering 559 m elevation made the annual mean temperatures of OL and MS in soil columns increase 0.84℃ and 0.82℃, respectively, but lowering 284 m elevation made the temperatures of OL and MS in columns actually decrease 0.55℃ and 0.56℃, respectively. Regardless of soil column transplanting and sampling periods, the activities of both invertase and urease in OL were significantly higher than those in MS. Moreover, those activities in OL varied more sharply with critical periods and elevation lowering than those in MS. The activities of invertase and urease in soils fluctuated to some extent with critical periods, but the highest and lowest activities of soil enzymes varied with soil layers, enzyme types and the elevations. On the whole, the activities of invertase in both OL and MS decreased from EGS to LGS, and then increased during DF and TP. The activities of urease in both OL and MS increased from EGS to DF, and then decreased in TP. Soil column incubation with lowering 284 m elevation significantly improved the activities of invertase in both OL and MS at EGS, OF and DF, but the incubation with lowering 559 m elevation significantly improved the activities of urease in both OL and MS at DF. The elevation, soil layer, sampling period and their interactions gave strong effects on the activities of invertase and urease in the alpine forest soil, and the responses of soil invertase and urease activities in the alpine forest to simulated climate warming varied greatly with different critical periods as affected by seasonal snow cover.