In order to study the intraspecific and interspecific relationship in the Quercus liaotungensis community, the intraspecific and interspecific competition intensity was investigated by using Hegyi competition index model for individual tree(IC) in Songshan Nature Reserve. Results show ed that the intraspecific and interspecific competition intensity in the community gradually decreased with the increase in forest DBH level. The trees, in terms of the intraspecific and interspecific competitio n's intensity, were in the order of Quercus liaotungensis>Fr ax inus chinensis>Ar meniaca sibirica> Carp inus turcz aninow ii. A ccording to the sample number statistics, the power function of IC=AD^-Bfor the competition intensity and the objective tree DBH distribution was most remarkable. The intraspecific and interspecific competition intensity in Quercus liaotungensis community was forecasted. When the diameter of Quercus liaotungensis tree was above 25cm,the change in competition intensity w as very small. Therefore, suitable artificial measures should be taken to promote plant grow th and enhance ecosystem stability