The Huangdi’s Internal Classic is a classic work of traditional Chinese medicine, and the theory of Yin and Yang is one of the important academic ideas in the Huangdi’s Internal Classic, which is of fundamental significance for the interpretation of human life activities. When discussing the opposites, complementarity, interroot and interuse of Yin and Yang, Yang is dominant, emphasizing that Yang strengthens Yin and Yin is secret, Yang governs Yin. As the core theory of traditional Chinese medicine, it plays an important role in guiding the clinical practice of traditional Chinese medicine and in all aspects of understanding, prevention, and treatment of diseases. Leucorrhea is one of the common gynecological diseases in women, with complex and variable symptoms that have a significant impact on women’s physical and mental health. The Huangdi’s Internal Classic, a classic work of traditional Chinese medicine theory, has profound discussions and unique yin-yang theory explanations for leucorrhea. Based on the theory of Yin and Yang in the Huangdi’s Internal Classic and in combination with modern medical research, this article will explore vaginal discharge in women, with the aim of providing new ideas and methods for clinical diagnosis and treatment.