| [Objective]To sum up and analyze Professor Liu Ying’s academic thought and clinical experience of treating chronic constipation by Acupuncture.[Methods]By learning from Professor Liu Ying’s clinical experience, collecting these cases to summarize Professor Liu Ying’s unique ideas of differentiation, treatment and acupoint selection on chronic constipation, and enumerated one case as evidence.[Results]Professor Liu Ying believes that the etiology and pathogenesis of chronic constipation are nothing more than deficiency and excess. Syndrome differentiation needs to differentiate deficiency and excess, cold and heat in the first place, combined with meridian differentiation. In addition to routine points selection, attention should be paid to Dai meridian, combination of lower confluent-front(Mu) point and selection of meridian divergence, nursing is also important.This treatment achieved good results.[Conclusions]Professor Liu Ying''s clinical experience of treating chronic constipation by Acupuncture is effective with accuracy on syndrome differentiation, precise and appropriate on acupoints selection, integrity on train and thought, which is worthy of further study and application.