Subalpine coniferous forest in western Sichuan is an important part of Sichuan forests. Because it mainly distributes in Jinshajiang River of upper reaches of the Yangtze River and its branches,Yalongjiang and Minjiang River and so on, it takes very important role in water conservation and soil protection in these area. Moreover,it also has a tremendous influence on economy and balance of ecosystem in this region and also as far as to the middle and lower reaches of the Yangtze River. Since 1940 s,natural coniferous forest was felt in grand scale,then spruce forests were planted on clear felled areas in succession. At present,there are 4.3×10⁴ hm² spruce plantation in these regions. But simple structure of artificial plant community had led to the degradation of forest ecosystem function. The soil organic matter and nutrient pool were studied under subalpine spruce plantation in western Sichuan. The results indicated that the soil organic matter and nutrient pool under spruce plantation degradated greatly. Decay rate and recycling period of spruce plantation were slower than those of secondary broad forest and natural coniferous forest,which led to that dry matter of forest floor and nutrients stored in the litter layer can't enter soil. Soil OM content,total N,total P and alkali-hydrolyzable N abruptly decreased with increasing of forest ages. The unitary composition of spruce plantation with less litter and nutrient returned to soil and the slower decay rate of litter were crucial factors inducing the degradation of the soil organic matter and nutrient pool in this area. In addition,human-induced disturbance,especially clearingout of litters and shrubs under plantation were another factor of the degradat ion of the soil organic matter and nutrient pool. It was suggested that the degradation of the soil organic matter and nutrient pool could be controlled by planting coniferou-shardwood and the rational thinning down after spruce plantation matured.