Abstract: Objective To investigate the effect of Safflower Yellow Injection combined with low molecular weight heparin calcium in prevention of deep vein thrombosis(DVT)after hip replacement(HR). Methods A total of 120 patients with HR were randomly divided into control group and observation group, with 60 cases in each group. Both groups were conducted with the same perioperative nursing. The control group was given low molecular weight heparin calcium subcutaneously to prevent DVT at 1 d after operation, and the observation group was given safflower yellow injection combined with low molecular weight heparin calcium to prevent DVT. Both groups were treated for 14 days and followed up for 3 months. The levels of prothrombin time(PT), activated partial thromboplastin time(APTT)and D-Dimer(D-D)were compared between the two groups at the time points of before operation, 3 days and 14 days after operation. Harris hip joint scores at the time points of before operation and 3 months after follow-up were compared between the two groups. The mcidence of DVT of two groups were observed Results The levels of PT and APTT in both groups were significantly lower than those before treatment, and the level of D-D was significantly higher than that before treatment(P<0.05). There were significant differences in PT, APTT and D-D levels before treatment and 14 d after treatment in the observation group(P<0.05). Compared with the control group, the levels of PT and APTT at 3 and 14 days after operation in the observation group increased significantly, and the level of D-D decreased significantly(P<0.05). Harris hip score at 3 months - after follow-up was significantly higher than that before operation in both groups(P<0.05). Harris hip score at 3 months after follow-up in the observation group was significantly higher than that in the control group(P<0.05). The incidence rate of postoperative DVT in the observation group was1.67%, which was significantly lower than 13.33% in the control group(P<0.05). Conclusion Safflower yellow injection combined with low molecular weight heparin calcium can effectively improve the hypercoagulable state of blood, promote the recovery of hip joint function and prevent DVT.