The content of the "Siku Quanshu" is very rich. According to its content classification, it includes 4 sections, 44 categories, and 66 subcategories. It is divided into four parts: Jing (classics), Shi (history), Zi (philosophical works), and Ji (literary works), hence the name "Four Treasuries". The Jing section includes 10 major categories such as Yi (Book of Changes), Shu (Book of Documents), Shi (Book of Songs), Li (Rituals), Chunqiu (Spring and Autumn Annals), Xiaojing (Classic of Filial Piety), Wujing Zongyi (General Meaning of the Five Classics), Sishu (Four Books), Yue (Music), and Xiaoxue (Primary Learning). Among these, the Li category is further divided into six subcategories: Zhouli (Rites of Zhou), Yili (Ceremonies and Rites), Liji (Record of Rites), Sanli Zongyi (General Meaning of the Three Rituals), Tongli (Comprehensive Rituals), and Zali (Miscellaneous Ritual Books). The Xiaoxue category is divided into three subcategories: Xungu (Exegesis), Zishu (Character Dictionary), and Yunshu (Rhyme Dictionary).
The Shi section includes 15 major categories such as Zhengshi (Standard Histories), Bianian (Chronological History), Jishi Benmo (Comprehensive Events), Zahist (Miscellaneous Histories), Bieshi (Separate Histories), Zhao Ling Zhu Yi (Imperial Decrees and Memorials), Zhuanji (Biographies), Shichao (Historical Abstracts), Zaiji (Records of Events), Siling (Seasonal Orders), Dili (Geography), Zhiguan (Official Positions), Zhengshu (Government Publications), Mulu (Bibliographies), and Shiping (Historical Criticism). Among these, the Zhao Ling Zhu Yi category is divided into two subcategories: Imperial Decrees and Memorials. The Zhuanji category is divided into five subcategories: Sages, Notables, General Records, Miscellaneous Records, and Separate Records. The Dili category is divided into ten subcategories: Palaces, General Gazetteers, Capitals and Prefectures, Rivers and Canals, Border Defense, Mountains and Rivers, Historical Sites, Miscellaneous Notes, Travelogues, and Foreign Records. The Zhiguan category is divided into two subcategories: Official Systems and Official Admonitions. The Zhengshu category is divided into six subcategories: Comprehensive Regulations, Ceremonies, National Finance, Military Administration, Laws and Orders, and Examination of Crafts. The Mulu category is divided into two subcategories: Texts and Epigraphy.
The Zi section includes 14 major categories such as Confucianism, Military Science, Legalism, Agronomy, Medicine, Astronomy and Mathematics, Divination, Arts, Catalogues, Miscellaneous Studies, Encyclopedias, Fiction, Buddhism, and Taoism. Among these, the Astronomy and Mathematics category is divided into two subcategories: Astronomical Calculations and Mathematical Books. The Divination category is divided into seven subcategories: Mathematics, Weather Prediction, Feng Shui, Divination, Fortune-telling Books, Physiognomy, Yin-Yang and Five Elements, and Miscellaneous Techniques. The Arts category is divided into four subcategories: Calligraphy and Painting, Music Scores, Seal Carving, and Miscellaneous Skills. The Catalogues category is divided into three subcategories: Instruments, Food Recipes, and Plants, Birds, Animals, Insects, and Fish. The Miscellaneous Studies category is divided into six subcategories: Miscellaneous Studies, Miscellaneous Research, Miscellaneous Discourses, Miscellaneous Evaluations, Miscellaneous Collections, and Miscellaneous Compilations. The Fiction category is divided into three subcategories: Miscellaneous Matters, Strange Tales, and Trivial Speeches.
The Ji section includes five major categories: Chuci (Songs of Chu), Individual Collections, Anthologies, Poetry and Prose Criticism, and Ci Qu (Ci Poems and Operas). Among these, the Ci Qu category is divided into five subcategories: Ci Collections, Ci Selections, Ci Discussions, Ci Spectra and Rhymes, and Northern and Southern Operas.
Apart from chaptered novels and theatrical works, the above classifications basically include all kinds of books in circulation. As for the authors, they include works by various types of people, including women, monks, Taoists, eunuchs, soldiers, emperors, and foreigners.