Tongxie Yaofang is a classic formula in the treatment of diarrhea caused by liver wood restricts earth, but the clinical application is not confined to diarrhea with pain. According to TCM thought of treating different diseases with the same method, it can also be used for the treatment of constipation caused by liver and spleen discord. Combining modern study and linking clinic, this article discussed the mechanism of this formula for the treatment of constipation, with a purpose to inspire thought and expand its clinical application range.