Abstract: Objective To investigate the clinical effects of arthroscopic radiofrequency ablation system in the treatment of post-traumatic synovitis of the knee joint. Methods Total 144 cases of post-traumatic synovitis of the knee joint in our hospital from August,2013 to June,2015 were enrolled and randomly divided into observation group and control group with 72 cases in each group.The control group received arthroscopic surgical treatment,while the observation group was given the arthroscopic radiofrequency.The outcome between the two groups were observed and compared. Results The postoperative recovery time and the incidence of joint effusion of the observation group were (9.24±1.24) d and 11.1% respectively that were significantly lower than (13.24±1.55) d and 33.3% of the control group (P<0.05).The postoperative 1 month Lysholm knee scores in the observation group and control group were (86.78±4.29) points and (80.13±5.29) points,respectively,that were significantly higher than the preoperative 1 d of (41.49±5.33) points and (40.98±4.89) points (P<0.05),while the postoperative 1 month Lysholm knee scores in the observation group were significantly higher than the control group (P<0.05).The postoperative 1 month knee joint activity in the two groups were significantly higher than the preoperative 1 d (P<0.05),while postoperative 1 month knee joint activity in the observation group were also significantly higher than the control group (P<0.05).The postoperative 1 month wound infection,edema,pain,skin pigmentation and other complications in the observation group were significantly lower than those in the control group (P<0.05). Conclusion Arthroscopic radiofrequency ablation system for post-traumatic synovitis of the knee joint has minimally invasive and good security,it can effectively improve knee function and knee joint activity,so as to promote the rehabilitation of patients.