Abstract: Based on the data of the permanent sample plots for continuous forest inventory from 1994 to 2019 in the eastern and western of Zhejiang province, the plots were divided into three groups, namely pine forest, Chinese fir forest and broad-leaved forest according to the dominant tree species. The mathematical expectation of stand duration was used to compare the durability of arboreal forest in the eastern and western Zhejiang. The results show that the durability of broad-leaved forest was the longest in both the East and the West, while that of pine forest was the shortest, but it tended to increase with duration, especially in the East. The durability of every group in the east was obviously longer than that in the west. Both in the east and the west, the arbor forest durability had positive relation with time.