This study was conducted to investigate abundance of breeding birds in relation to forest environment, to figure out the influential factors in abundance of breeding birds and to get the basic data for effective management of the bird community in Jirisan National Park. For this purpose, this research selected 4 main hiking trails as survey points and conducted a survey on breeding bird species and forest environment from April to August in 2007. The study results are as follows: The number of the birds observed during the breeding season was 33 species at the elevation of 300 meters to 1,900 meters. This research made a regression analysis of 13 bird species appearing at more than 30% of all surveyed points, species richness, and richness in the number of individuals. As a result of making a simple and multiple regression analysis of the factors, among the forest environment factors, that have an effect on richness in bird species, each species was found to be less influenced by an elevation. In addition, this analysis revealed that among the forest environment factors, coverage of tree-1 layer(>12m), tree height, coverage of shrub layer(2${sim}$0.5m), slope, coverage of subtree-2 layer(4${sim}$2m) appeared as more influential ones on the variation of abundance in more species than an elevation itself. That explains why it is necessary to continuously maintain and manage the coverage of tree-1 layer(>12m), tree height, coverage of shrub layer(2${sim}$0.5m), slope, and coverage of subtree-2 layer$(4{sim}2m)$, etc. for the preservation and management of bird species in a breeding season at Jirisan National Park.