In order to explore the effects of different altitudes and canopy closures on the decomposition of leaf litter of Qinghai spruce (Picea crassifolia), four altitudes (i.e. 2850 m, 3050 m, 3250 m, and 3450 m) and three kinds of canopy closure (high, medium, and low) were selected in this study. Field decomposition net bags were used to study the litter decomposition rate (K), nitrogen (N), and phosphorus (P) content changes of leaf litter during decomposition. The results showed that the rate of mass loss increased with time. The decomposition rate decreased first and then increased with time. The sequence of decomposition rate at different altitudes was K₃₄₅₀ > K₃₀₅₀ > K₃₂₅₀> K₂₈₅₀, and the order of decomposition rate at different canopy closure was K_low > K_medium > K_high. Qinghai spruce leaf litter decomposition time needed for 50% and 95% mass loss was about 5.3 year and 22.7 year. During the decomposition of the leaf litter, the changes of N and P content and accumulation coefficient at different altitudes and canopy closure were different, and were related to seasonal changes. Results obtained in the study would lay the foundation for geochemical cycle in the forest ecosystem of Qilian Mountains.