Abstract: OBJECTIVE In this paper, we introduced the influencing factors of me-too drugs’ on therapeutic effects. METHODS The related references at home and abroad were summarized in recent years. RESULTS There are three major influencing factors, including quality of active pharmaceutical ingredient and drug polymorphism, drug preparation and the evaluation method of biological activity. Among them, drug preparation and drug polymorphism are two important uncontrolling factors in quality standard. CONCLUSION It provides a reference to improve the quality and quality standard of me-too drugs.