Abstract: Experiments were conducted in 2012 at young growth of Pinus yunnanensis of burned-over area in 2001 in Xishan Forest Farm of Kunming, Yunnan province, with different thinning intensities(10%, 20% and 30%). Investigation in 2014 demonstrated that mean tree height growth increased by 20% at sample plot with 30% thinning and control(no thinning), while 10% at that with 10% and 20% thinning plots. Height growth of dominants had no great difference among different treatments and control, but mean DBH increment had significant difference, 10.96% at control, 41.77 at sample plot with 30% thinning, about 30% at sample plots with 20% and 10% thinning. The experiments indicated that different thinning treatments had no evident effect on tree height growth, but could improve diameter growth.