Abstract: In this articl,the investigation and analysis were made of the stand structure, canopy density, density, volume, productivity and stem of Japanese larch plantations by selecting Japanese larch sapling forest, mid-age forest, near-mature forest in the Northeast mountain, southwest mountain, west mountain canyon areas of the Sichuan Basin. According to the change of Japanese larch plantation DBH current annual increment decreasing time, the recovery time of canopy density and a comprehensive analysis of the natural thinning,the thinning technology was proposed, and the reasonable suggestion was put forward on the relationship between planting density and reasonable thinning of Japanse larch plantation.