Objective To investigate the early diagnosis of lower l imb deep vein thrombosis (DVT) after major orthopedic surgeries. Methods From October 2005 to June 2009, color doppler sonography and hemorheology detection were carried out for 62 cases undergoing first total hip arthroplasty (THA), 14 cases undergoing total knee arthroplasty (TKA), and 86 cases undergoing hip fractures surgery (HFS) before operation and 1, 7, 14 days after operation. The plasma D-dimerlevels of the DVT were also examined for the THA patients before operation and 3 days after operation. Of all cases, therewere 89 males and 73 females, aged from 34 to 74 years (51.5 years on average). After operation, all the patients were treated with the regular low molecular weight heparin sodium against DVT. Results After operation, 17 cases (10.5%) developed DVT, including 8 THA cases, 1 TKA case, and 8 HFS cases. Preoperative color doppler sonography showed no abnormal echo, normal b blood flow signal, and normal periodical variation in vein blood flow without regurgitation. Postoperative examinations showed that the vascular occlusion of common femoral vein and popl iteal vein occurred in DVT patients. There were significant differences (P lt; 0.05) in whole blood viscosity between patients with DVT and without DVT after 1, 14 days and no significant difference (P gt; 0.05) before operation and 7 days after operation. There was no significant difference (P gt; 0.05) in plasma viscosity and erythrocyte aggregation index, between patients with DVT and without DVT pre- and postoperation. There was significant difference (P lt; 0.05) in erythrocyte deformation index between patients with DVT and without DVT 14 days after operation. The preoperative plasma D-dimer levels of patients with DVT and without DVT were (372.00 ± 148.62) ng/mL and (369.00 ± 141.03) ng/mL, respectively, showing no significant difference (P gt; 0.05); the 3 days postoperatively levels were (574.00 ± 217.29) ng/mL and (391.00 ± 120.16) ng/mL, respectively, showing significant difference (P lt; 0.05). Conclusion Color doppler sonography in combination of hemorheology and plasma D-dimer examination can be beneficial for the early diagnosis of DVT in major orthopedic surgeries.