Yudu Mountain is located in the deep mountains, seldom visited by people, with beautiful scenery and quiet environment. Yudu Mountain is a little-known virgin land in Beijing; Yudu Mountain is the most primitive green memory preserved by nature; Yudu Mountain is the best choice for modern people to return to nature. Yudu Mountain is a pearl hidden in the mountains, and it has the same desire as modern people, which is the highest realm of "harmony between man and nature". The beauty of Yudu Mountain lies in the mountains, rocks, forests, springs, waterfalls, flowers, and grass, and the feeling of nature lies in the clear, quiet, and wild. Yudu Mountain is along the Houhe River in the south and the Gucheng River Valley. It starts from the Haituo Peak, the second highest peak in Beijing with an altitude of 2,241 meters in the west, and ends at Longqing Gorge in the east. It covers an area of more than 100 square kilometers, with an altitude of 580-1,589 meters in the territory. The core and essence of the area is about 58 square kilometers. The area is part of the Jundu Mountain Range, the remnant of the Yanshan Mountains, and is located at the western end of the Yanshan Depression Zone. The landform is mainly composed of gullies, middle mountains, and valley erosion terraces. There are two rivers in the area, one runs through Yudu Mountain to Sancha River, and the other runs through Wulipo to Sancha River. Both rivers originate from Haituo Mountain and merge into one at Sancha River and flow into Longqing Gorge. Since Haituo Mountain is a place with developed granite fissures and dense vegetation in the upper reaches, the bedrock fissure water is abundant, so the river water volume is large. Even in the dry season, there is spring water supply, and the river flows all year round. Because of the good hydrological conditions, few human activities, and closed nature, the plants in this area grow luxuriantly and in a wide variety of species. According to the survey of Capital Normal University and Forestry University, the trees are mainly composed of valley miscellaneous forests dominated by pine, birch, mountain poplar, Liaodong oak, linden and Beijing lilac; the shrubs are mainly composed of mountain elm, bicolor Lespedeza, flat hazel, tiger hazel, Spiraea, Rhamnus, Prunus armeniaca, Vitex, Prunus armeniaca, etc. The herbs are mainly herb communities, and some Vitex and shrubs are combined. The vegetation coverage here is high (up to 100% around Yudu Mountain), with many species and good growth. It is a natural northern botanical garden. Wildlife resources are also very rich. According to the Biology Department of Capital Normal University, there are 184 species of vertebrates, including more than 20 mammals, 11 orders, 29 families, and 125 species of birds. There are 16 species of wild animals listed as key protected by the state, 14 species listed as key protected by Beijing, and 16 species listed as generally protected by Beijing. The climate here is a typical mountain climate with obvious vertical distribution. Due to the high altitude, the temperature here is lower than that near the county seat, the daily difference is larger, and the precipitation is more than that near the county seat.