Objective: Whether to intra-articular drain in total knee arthroplasty (TKA) is currently controversial. The purpose of this study is to investigate the effect of whether to place intra-articular drainage in total knee arthroplasty on blood loss and joint function recovery. Methods: A retrospective analysis of 147 patients with end-stage knee osteoarthritis (KOA) who underwent TKA at the First Affiliated Hospital of Nanjing Medical University from September 2021 to October 2022 was performed, and they were divided into a drainage group and a non-drainage group according to whether or not to place drainage during the surgery. Observe and compare the postoperative blood loss, knee function recovery index, postoperative complications and follow-up results of the two groups. Results: A total of 147 patients were included,53 in the non-drainage group and 94 in the drainage group. Compared with the hidden blood loss of (1262.85±563.46) ml in the non-drainage group, that in the drainage group was less as (906.94±438.41) ml, and the difference was statistically significant (P<0.01). There was no significant difference in blood transfusion rate and total blood loss between the two groups (P>0.05). The degree of postoperative swelling in the non-drainage group was higher than that in the drainage group, and the degree of swelling of the lower limbs at 3 days postoperatively was (9.31±4.47%) in the non-drainage group and (7.74±3.75%) in the drainage group, with a statistically significant difference (P=0.025). Postoperative active knee ROM (range of motion, ROM) was significantly increased in the drainage group compared to the non-drainage group (P<0.001). Pain was significantly higher in the drainage group than in the non-drainage group at 3rd day postoperatively (P=0.029). There was no significant difference between the incidence of postoperative DVT in the two groups of patients (P=0.552), and the incidence of postoperative ecchymosis in the non-drainage group (79.25%) was higher than that in the drainage group (52.13%), with significant difference(P=0.001). The postoperative incisions of patients in both groups healed at stage I A, and there were no infections such as redness, swelling, oozing or even fat liquefaction. Drainage tube condition of patients in the drainage group was observed, without poor drainage, continuous bleeding, dislodging or even fracture of the drainage tube. There were no cases of infection in both groups during the follow-up period. There was no significant difference between the two groups in the follow-up results of the knee joint function recovery and pain at 1st month and 3rd month after the surgery (P>0.05). Conclusion: Intra-articular drainage in TKA can reduce hidden blood loss and decrease the pain and swelling in the early postoperative period compared with that without drainage. Keywords: knee osteoarthritis, total knee arthroplasty, drainage, hidden blood loss, swelling, pain