Located in the northwest of Donghai County, it is near Yushan Mountain, also known as "Yushan Hot Spring". It is a newly developed tourist hot spring in Lianyungang City. Hot springs were found in the Tang Dynasty and were recorded in historical records. This shows that people developed and utilized it more than a thousand years ago. At that time, the hot spring was just two small pools, hot groundwater, constantly gushing out of the ground, flowing wildly, people called "Tangquan". In 1972, a self-flowing well was drilled here. The depth of the well was more than 500 meters, the water temperature was as high as 82 degrees Celsius, and more than 900 tons of water were injected every day. At present, Donghai Hot Spring has been developed into a sanatorium. It is a pleasant thing for domestic and foreign tourists to drive to Lianyungang after having a good view of the sea, mountains and historic sites, and to wash up the dust and eat plenty of food. According to the relevant unit tests, Yushan hot spring belongs to sodium-calcium type water, rich in sodium, calcium, magnesium, zinc and other elements, especially radon content of radioactive gas, which exceeds 5.6 Marshall units in a liter of water. It has important medical value and has obvious curative effect on arthritis, hypertension and various skin diseases. Yushan spring water is transparent and clear, smooth and refreshing. It does not have the unpleasant sulfur smell of ordinary hot springs and does not need soap when bathing. The water quality is comparable to that of Huaqing Pool in Xi'an and Tangshan Hot Spring in Nanjing. Drinking a slightly salty hot spring water after a bath not only increases appetite, but also cures gastrointestinal diseases.