Abstract: Four kinds of thinning treatments were designed including thinning from below, thinning from above, mechanical thinning and crop tree relea〖JP2〗se with the same thinning intensity on the 14-year-old pure Cunninghamia laceolata and Pinus massoniana plantations in Guangxi, and 6 kinds of size inequality indices were applied including stand deviation, variation coefficient, skewness, Gini coefficient, Ku〖JP〗znetz coefficient and Lorenz asymmetry coefficient to evaluate the change of individual volume inequality after the 4 kinds of thinning regimes applied. The results showed that stand deviation, variation coefficient, Gini coefficient and Kuznetz coefficient decreased and skewness increased after thinning from below or above compared with before thinning, while after crop tree release these four indices increased and skewness was uncertain. Lorenz asymmetry coefficient increased after thinning from below while it decreased after thinning from above or crop tree release compared with before thinning. There was no distinct rule for the 6 kinds of size inequality indices after mechanical thinning. The size inequality increased after crop tree release while it decreased after thinning from above or below. The study suggested that Lorenz curve, Gini coefficient and Lorenz asymmetry coefficient could be used to compare the size inequality statically and dynamically among different stands, and could be discriminated the difference of size inequality caused by the different thinning regimes. Lorenz asymmetry coefficient even could be applied to tell the size inequality was mainly from the larger or smaller individuals. Crop tree release method in closetonature management could lessen the competition pressures of crop trees and increase the size inequality of the stand effectively which would be helpful to maintain the dominant position of crop trees.