The yang-deficiency constitution and yang-deficiency syndrome are compared and analyzed to make clear the connotation scope of yang-deficiency constitution. Then,through the analysis on the theory of yang-deficiency constitution in ancient medical books,it finds that yang-deficiency constitution shows its own characteristics,which affect the tendency of disease,medication and health preservation. Based on this and upheld the concept of“searching for the root cause of disease in treatment and root cause originating in constitution”,it is proposed that the primary dysmenorrhea in women with yang-deficiency constitution should be treated with internal and external regulation,and the principles of supporting yang,tonifying yang and protecting yang should be emphasized.