Objective：To explore the effect of postoperative limb positions on limb swelling and range of motion after total knee arthroplasty. Methods：Between June 2014 to June 2016，100 patients in our hospital who received primary total knee arthroplasty were recruited and randomly divided into two groups（n=50）. In the Group A，50 patients had their lower limb placed with the hip flexed 30° and the knee mild flexed 30° for the first 72 h after operation. In the Group B，50 patients had their lower limb placed with the hip flexed 30° and the knee high flexed 60° for the first 72 h after operation. Degree of swelling，subcutaneous ecchymosis area，the number of blister and skin temperature after 72h were observed，and angles of passive flexion and active flexion of the operated knee were recorded. Results：There were statistically significant differences in the degree of lower limb swelling，subcutaneous ecchy－mosis area，number of the blister，and skin temperature between two groups（P<0.05）. There was also a significant difference in the angles of active flexion of the operated knee（98°±8.91° vs. 83°±7.65°，P=0.023），while there was no significant difference in the angles of passive flexion（115°±12.16° vs. 110°±10.38°，P=0.072） between two groups. Conclusion：Findings of this study indicate that postoperative position of the hip by 30°，with the knee flexed 30°，is more effective than the position hip flexed 30°with the knee flexed 60°，in alleviating knee swelling and increasing range of motion.