Built in 1938, covering an area of more than 11,100 square meters, it is a Japanese garden style garden designed by Japanese landscape architect Sato Cang. The garden is a place for Puyi and his "queen and concubine" to relax and entertain. At the beginning of the construction, there was only a rockery, swimming pool and horseback riding ground. Thereafter, an air defense basement was built in Dongyu Garden, and a "nation-building temple" dedicated to the Japanese Royal ancestor "Tianzhao God" was built on the original horseback riding ground. The rockery is situated in the south of the garden. Its mountain-like vein is made up of Changbai Mountain, the birthplace of the Manchu people. It can be seen from the waterfalls of Changbai Mountain.