Objective The aim of this retrospective study is to evaluate the clinical effect of arthroscopic internal drainage of popliteal cyst. Methods Twenty patients who had undergone arthroscopic internal drainage treatment from March 2016 to March 2019 were retrospectively analyzed in therapeutic effect with Rauschning and lindgren classification. Results The intra-articular diseases were found intraoperatively, including osteoanhritis in 22 cases, rheumatoid arthritis in 1 cases, gouty arthritis in 1 cases. All patients were followed up for 10 to 18 months with average of 14 months.Symptoms were alleviated postoperation obviously.There were no blood vessel or nerve damage ,no incision complications. There was 1 case of recurrence that occurred in 1 month postoperation. At final follow-up,there were 21 cases in grade 0 , 2 cases in grade 1 and 1 cases in grade 2 ,according to the Rauschning and Lindgren classification. Conclusion Arthroscopic internal drainage of popliteal cyst is a kind of safe,mini-invasive and effective surgical technique.