Objective To observe the therapeutic effect and action mechanism of Shugan Granule on mice with mammary gland hyperplasia caused by liver qi stagnation, and explore its neuroendocrinology regulation mechanism for this disease. Methods Female mice were divided into blank group, model group, traditional Chinese medicine group and western medicine group. In the experiment, the blank group had no intervention, the other three groups were given chronic compound stress for 10 weeks. From the 11 th to 14 th week, the blank group and model group were given distilled water by gavage, while the traditional Chinese medicine group and western medicine group were given Shugan Granule and tamoxifen by gavage respectively. The biological characteristics of mice were observed and recorded after 0, 10 and 14 weeks. At the end of the experiment, the mice were killed, and the hypothalamus was stripped to detect neurotransmitters; the blood was taken to detect serum hormones; the mammary gland and its surrounding skin were taken under aseptic conditions for pathological observation. Results At the end of modeling, except the blank group, the other three groups of mice showed a series of desperate behavioral changes, such as fatigue, hair removal, weight loss, immobility time growth and so on. Compared with the other groups, hyperplasia of mammary glands was decreased, the secretion of hypothalamic neurotransmitters NE and 5-HT was inhibited, and the serum hormones CRH and ACTH were increased in the Chinese medicine group. Conclusion Shugan Granule can regulate the neuroendocrine system and reduce the degree of mammary gland hyperplasia in mice effectively.