Wensu Pavilion was built between 1782 and 1783 during the reign of Emperor Qianlong, and is a three-story building that seems like a two-story building from the exterior, imitating the architectural form of the Tianyi Pavilion in Ningbo. Each story was furnished with beds, writing desks, thrones, long tables for incense burners, palace fans with plumes, red sandalwood kang table, table for guqin, square stools, hanging scrolls of painting or calligraphy, and others. The pavilion is named after sujian qiuben (lit. ‘going against the stream to seek its origin’) taken from the Book of Poetry, and was one of the seven pavilions for collecting the Siku Quanshu of the Qing Dynasty. Divided into four bibliographic categories of Confucian classics, histories, miscellaneous schools, and collections, the Siku Quanshu has collected over 79,000 volumes in more than 3,400 varieties of books, making it the largest series of books preserved from the history of China.

The roof, walls, doors, and windows of the Wensu Pavilion are mostly black, white, blue, and green in color. The colored painting patterns were selected from the simple and elegant themes of the books, which formed a clear-cut contrast with the other buildings in the palace with red and gold as the main colors. The use of colors is mainly based on the theory of five elements. As a book-collecting building fears fire disasters the most, gold and red colors symbolizing fire were used in this building as little as possible. On the other hand, black as a symbol of water sees its presence in black tiles of the Wensu Pavilion, with the intention of suppressing fire with water.