Abstract:The illustrations of a French book revealed the reason why the Daxitian Glazed pagoda in Xiyuan Beihai was destroyed by lightning in the 23rd year of Emperor Qianlong of the Qing Dynasty (1758). It solved the mystery of the burning of the Daxitian glazed pagoda, but also led to the exploration of the royal pagoda building activities around the 20th year of Qianlong (1755). By combing the archives and documents, we clarify the beginning and end of the royal pagoda building activities in Xiyuan Beihai, Qingyi Garden and Chengde summer resort around the 20th year of Qianlong (1755). On this basis, we try to restore the Daxitian glazed pagoda, reproduce the unrealized skyline of Beijing with the help of virtual technology, and then speculate the Emperor Qianlong's assumption and intention of the spatial pattern of Beijing.