Abstract: Based on the mathmatical methods and computer technology, the paper deal with the succession of Pinus massoniana communities on the natural condition in the mountains of northern Fujian Province, China, based on samples from 82 10×10m2 plots and 320 2×2m2 plots. Successional stages of all species in the area were divided into three groups, failing, transition and progressing according to their species association coefficients of X2 statistics. The sere was reconstructed and the five stages were defined from the result of the relative important value of the three groups with the division method of optimization.