This paper discussed the disease characteristics,etiology and pathogenesis of menstrual diarrhea with syndrome of liver-spleen disharmony and prescription composition and compatibility of“Tongxie Yao Fang”(important formula for diarrhea with abdominal pain). Through the analysis of physiological and pathological features of women in menstrual period,combined with related ancient books and modern clinical research about diarrhea,it found that menstrual diarrhea with syndrome of liver-spleen disharmony was the most common form. “Tongxie Yao Fang” is a representative formula of invigorating spleen and restraining liver. Analyzing its prescription characteristics could provide reference for the clinical syndrome differentiation and treatment of menstrual diarrhea.