The Beijing Olympic Forest Park is the largest city park in Beijing. Since the Olympic Forest Park was built, the plant species composition and sources have not been reported. We researched the composition and distribution of plants in the Beijing Olympic Forest Park based on the field survey data. We found that the park has the vascular plant of 295 species belonging to 75 families, 203 genera, including 60 species of arbor, 57 species of shrubs, 170 species of herbs and 8 species of vines. It has 179 local species and 116 exotic species, including four invasive species in all plant species. It has 183 cultivated plants species, and 112 wild plant species. In the park, the proportion of cultivation of local shrubs species (50.00%) is higher than in the built-up areas of Beijing (27.00%), and there are more domestic introduction species. Finally we put forward some suggestions on increasing plant species, keeping local kind of use, and reducing foreign species.