The intraspecific and interspecific competitions intensity of C. kawakamii seedlings in C. kawakamii Nature Reserve were quantitatively analyzed by using Hegyi’s competition index model. The results showed that the intraspecific competition intensity of C. kawakamii seedlings decreased gradually with increment of seedlings height. The interspecific competition intensity in C. kawakamii community was in order as Litsea subcoriacea＞Camellia octopetala＞Machilus grijsii＞Calamus thysanolepis＞Itea oblonga＞Schima superba＞Antidesma japonicum＞Diplospora dubia＞Engelhardtia fenzelii＞Clausena dentata＞Syplocos lancifolia＞Ardisia punctata＞Syzygium buxifolium＞Distyliopsis dunnii＞Syzygii buxifolii＞Chloranthus glabra＞Castanopsis kawakamii＞Castanopsis fargesii＞Maesa japonica. The competition intensities of heliophytes species were strong with obvious height advantage, while those of skiophytes species or seedlings with shade-tolerance at early growth stage were weak and grown slowly. The competition intensities between the competitive trees and the objective trees with the objective trees’ height conformed to power function distribution which showed significantly negative correlation. At the same time, the intraspecific and interspecific competition intensities of C. kawakamii seedlings were also simulated and forecasted. The results showed that the intraspecific competition intensities of C. kawakamii seedlings at the early growth stage were at medium level. With the height of seedlings increasing, the intraspecific competition of C. kawakamii seedlings was weak gradually, while the interspecific competition of C. kawakamii seedlings obviously increased, and the C. kawakamii population had the tendency of deterioration. In order to improve the survival of C. kawakamii seedlings, the C. kawakamii seedlings should be protected strengthen and promoted growth by artificial cultivations when the seedling height were under 125 cm. The competition intensity of C. kawakamii seedlings tended to be stable when the height reached up to 125 cm.