Abstract: Abstract: Numerous results of carbon (C) emission of the subalpine dark conifer forest showed more or less differences for the great and complicated environmental temporal-spatial variation in the Gongga Mountain region in Southwestern China. For a more exact estimation of soil C emission in the subalpine forest and a more clear understanding of its impacting factors in the Mount Gongga, with the Li-6400-09 chamber, the soil CO2 emission and the main environment factors of the Abies fabri forests were studied. The results showed soil C storage (291.0 t/hm2, 49.8% of the forest ecosystem) in the mature Abies fabri forest is higher than that (63.8 t/hm2, 30.7% of the forest ecosystem) in middle-aged Abies fabri forest, which indicated the effects of stand age on soil C storage. Overall, the annual variation of the soil C emission rate in the mature Abies fabri forest showed a similar tendency as that in the middle-aged Abies fabri forest. For both of the mature and middle-aged Abies fabric forests, the monthly soil C emission rate in the growing season (May to October) is much higher than that in the non-growing season (November to the next April), and the maximum in summer is 5~6 times as large as that of the minimum in winter; while the soil C emission rate each month in the mature Abies fabri forest is on average 1.5 times as large as that in the middle-aged Abies fabri forest. The soil temperature, soil moisture and monthly soil CO2 emission rate generally fluctuate in synchrony under the warm and humid climate during growing season. The peak of monthly soil CO2 emission rate in the middle-aged Abies fabri forest, 34.53 kg C/(hm2·d), occures in July (the warmest and the most humid month for both of the forest soils in middle-aged and mature Abies fabri forest), while the valley, 6.96 kg C/(hm2·d), appears in February (the coldest and driest month for the forest soils in middle-aged Abies fabri), with an average of 16.26 kg C/(hm2·d) and a variation coefficient of 0.54. The maximum of monthly soil CO2 emission rate in the mature Abies fabri forest, 55.34 kg C/(hm2·d), delays one month to August, and there are two small peaks in May and December, respectively; while the minimum, 9.50 kg C/(hm2·d), delays to January, later than December that is the driest month for the mature Abies fabri forest soil, and earlier than March, the coldest month. The soil C emission rate in the mature Abies fabri forest has an average of 24.57 kg C/(hm2·d) and a variation coefficient of 0.61, which implies the mature Abies fabri forest ecosystem has more self-adjusting function. The daily average soil CO2 emission rate has more obvious correlation with soil temperature in 5 cm depth (the representative layer for the microbial activity and upper soil average heat condition) rather than air temperature, relative humidity, precipitation, and photosynthetically active radiation (PAR) in both the mature and middle-aged Abies fabri forests (r=0.73, P<0.05; the two forests are the same), and the fitted curves showed their exponential relationships (R2=0.60 for the mature forest and R2=0.56 for the middle-aged forest). In the subalpine cold-humid condition, without the high temperature inhibition, the soil moisture (monthly variation ranged from 14% to 30%) can hardly become the limiting factor, while the soil temperature plays a key role on soil C emission. Under the typical Intergovernmental Panel on Climate Change (IPCC) series of emission scenarios (SRES), i.e., B1, A1B and A2, the soil C emissions are expected to be increased by 15%, 25% and 31% respectively from the mature Abies fabri forest soil, and by 13%, 21% and 17% respectively from the middle-aged Abies fabri forest soil. It indicates that the stand age should be attached more importance in the C emission investigation and monitoring. The research provides basic data and references for the C balance estimation in the region under changing environment.