Based on clinical epidemiological data， it is believed that qi deficiency constitution is closely related to allergic diseases. According to the fundamental principles of traditional Chinese medicine （TCM） constitution theory， the intrinsic connection between qi deficiency constitution and allergic diseases is analyzed from the perspectives of inherited endowment， life process， environmental restriction， and the interplay of form and spirit. This paper discusses the key points of regulating qi deficiency constitution to prevent allergic diseases in three stages， prevention before illness， prevention of disease progression， and prevention of recurrence after recovery. It also distinguishes the treatment directions for regulating qi deficiency constitution to treat allergic diseases based on different disease locations such as the lung， spleen， and kidney. This aims to expand new ideas for the research on qi deficiency constitution and allergic diseases as well as the prevention and treatment of allergic diseases.