Background: Knee osteoarthritis is a common problem for which acupuncture provides effective analgesia. Although acupoint selection affects the effectiveness of acupuncture, the basic rules of acupoint selection are little understood. This study aims to investigate the principles of acupoint selection and characteristics of acupoints used for knee osteoarthritis. Objective: To determine the frequency of acupoint and meridian applied in treating knee osteoarthritis by using data mining analysis, and to provide valuable prescription in acupuncture treatment of knee osteoarthritis. Method: PubMed, China National Knowledge Infrastructure, and OVID were searched for clinical trials published in English or Chinese from January 2016 to Dec 2020 evaluating the effect of acupuncture on knee osteoarthritis, with or without methods of randomization and/or control. Results: A total of 99 articles were included, involving 51 acupoints, with a total frequency of 705 times. Among them, the acupoints with higher accumulative application frequency are Du Bi ST35 (93 times), Nei Xi Yan EX-LE04 (86 times), Xue Hai SPI0 (76 times), etc.; the commonly used acupoints are mainly distributed in Stomach meridian of Foot-Yang Ming, Spleen meridian of Foot-Tai Yin, Gall Bladder meridian of Foot-Shao Yang and non - meridian. Du Bi ST35 and Nei Xi Yan EX-LE04 is the most common combination of acupoints, and most of them are the combination of proximal acupoints and far and near acupoints; through the analysis of association rules, 20 groups of acupoint association rules were obtained. Conclusion: It is feasible to use data mining to analyse the selection and compatibility of acupuncture points for knee osteoarthritis, and this study can provide a corresponding reference for clinical treatment.