Abstract: Gaichun Garden is located at the back side of Longevity Hill in the Summer Palace, which is an existing garden buildings ruin built in early Qingyi period. This garden imitated Yongji Temple in Nanjing, and reflected Jinshan Mountain and Jiaoshan Mountain in Zhenjiang. The garden construction skillfully made full use of natural rocks to reshape local mountain terrain and create a momentum of bird's eye view. The design of mountain and rock cleverly used some certain techniques to leave some parts and remove some parts, Qingkexuan cave and natural stone wall bring out the best in each other, which is a punchline of the whole garden. This garden contains profound cultural connotation, including Confucianism, Taoism, Buddhism, and so on, which is an ideal physical embodiment for Qianlong Emperor. Through relevant literature research, field survey, mapping and rehabilitation design, the art of this garden was analyzed to explore and discuss the garden owner's aesthetic of Qianlong emperor, so as to promote the work of conservation and presentation of the back side runs of Longevity Hill.