The Margallah hills are home of diverse flora and fauna in Pakistan. The whole study of Phytosociological Analysis of State of Existing Vegetation in Reserved Forest, compartment 20 of Margallah Hills National Park, basically aimed at % vegetation cover, stood 78%, shrubs and grasses cover, in total 79 vegetative species were found in the area, however 7 remained unidentified forage productivity remained 1160 kg/ha, animal units was almost .03. Pressures and threats to park and particular compartment are directly and indirectly increasing day by day. Major pressures are increasing human population, overgrazing by animals, environmental pollution, like water contamination and forest fires. A thing of concern was the identification of a fast depletion of indicator species Dodonea viscosa. Forest fires occurred 1-2 times annually. All these factors show that vegetation is declining in the compartment.