Objective: Investigating the effect of CsA for reducing fibrous tissue hyperplasia after KTP Nd∶YAG laser recanalisation, guide the clinical use of medicine to reduce lacrimal duct stenosis relapse. Method: Making the animal model of lacrimal duct obstruction, dividing them into two groups, and injecting saline solution and CsA separately. Result: The appearance of lacrimal duct part obstruction and fibrous tissue hyperplasia is later in the CsA group, and the fibrous tissue hyperplasia is lighter. Conclusion: CsA can reduce fibrous tissue hyperplasia after KTP Nd: YAG, and improve the success rate of KTP Nd: YAG laser recanalization.