Abstract: The self thinning law, life cycle strategy and occurrence of disease and pest injury as well as natural regeneration of different age of Pinus sylvestris var. mongolica community in Yulin area were investigated.The results showed that: Yulin area community was not a stable community, however, the competition ability here was very strong, which was in the process of adaptation to the local site conditions and climatic conditions. In the future, pest outbreaks should be prevented in forest management, and natural regeneration should be stimulated artificially.