Abstract: The experimental plots were set up on a 9-year-old Chinese fir plantation, where different thinning methods, such as thinning from above, thinning from below, thinning from above and below, mechanical thinning and control plot were carried out in 1975. The thinning intensity is about 30 Percent of the number of trees. The height. breast diameter, hasal area of trees were measured in 1975, 1978, 1982 and 1986 respectively. The results show that different thinning methods have different effects on the growth and yield of the Chinese fir plantations. hased on the analysis of the tree increment, mechanical thinning is the best when the first thinning is carried out on a young Chinese fir plantation.