Abstract:A comparison was made on the plant divenity of Pinus. koraiensis forest after selective cutting and Betula platyplla secondary forest formed after clear cutting in the .P.koraiensis forests in Changbai Mountain forest region in China. The results show that the divenity of the whole community and undergrowth of B. platyphylla secondary forest are. higher than that of any type of P koraiensis. forests. The divenity of the whole community and tree layer of P korairensis virgin forest with slight-. selective cutting are the highest among all P koraiensis forests, which is the result of the forest adapting long term succession and species adaptation. Because B. platyphylla forest is in the second succession stage, more shade- tolerant tne species had colonized the community. Besides, solar radiation is the B. platyphylla forest is better so that the undergrowth developed well, and the diversity of woody plant is very high. At last. The relationships between diversity and evenness, haibtat of. The communities are analysed.