To explore clinical effect of arthroscopic debridement combined with platelet-rich plasma (PRP) injection for Kellgren-Lawrence(K-L) gradeⅠ-Ⅲ knee osteoarthritis (KOA) . Totally 117 patients with KOA who underwent arthroscopic debridement combined with injection from November 2015 to January 2019 were retrospectively analyzed. According to different injection drugs, the patients were divided into sodium hyaluronate group(group A) and PRP group(group B). In group A, there were 60 patients, including 27 males and 33 females, aged from 49 to 67 years old with an average age of (54.1±4.8) years old;12 patients with gradeⅠ, 23 patients with gradeⅡand 25 patients with grade Ⅲ according to K-L clssification, 2 ml(20 g) sodium hyaluronate was injected into knee joint after intraoperative, 1, 2, 3 weeks after operation for 4 times. In group B, there were 57 patients, including 25 males and 32 females, aged from 47 to 70 years old with an average of (55.8±5.0) years old, 10 patients with gradeⅠ, 20 patients with gradeⅡand 27 patients with grade Ⅲ according to K-L classification, injected 5 ml PRP at the same time. Postoperative complications was recorded between two groups. Postoperative visual analogue scale(VAS) and Lysholm score at 3, 6, 12 months were used to evaluate improvement of knee pain and joint function. All patients were followed up for 12 to 19 months with an average of (14.1±1.6) months. There was no significant difference in postopertaive complications between group A and group B (P>0.05). Postoperative VAS score in group A at 3, 6, 12 months were 3.0±0.8, 2.0±0.8, 2.6±0.9 respectively, and 2.9±0.8, 1.9±0.7, 2.2±0.8 in group B respectively; and no differnece at 3 and 6 months after operation between two groups (P<0.05), while VAS score in group B was higher than group A at 12 months after operation(P<0.05). Postoperative Lysholm score in group A at 1, 6, 12 months (86.6±1.8, 93.1±2.0, 86.7±1.7) were lower than group B(88.9±1.9, 95.0±2.0, 89.0±1.9)(P<0.05). Arthroscopic debridement combined with sodium hyaluronate or PRP injection for K-L gradeⅠ-Ⅲ KOA could effectively relieve pain and improve joint function with higher safety in short term, but the medium-long-term effect of PRP injection is stable.