Objective To analyze the characteristics of proximal deep vein thrombosis (DVT) after total joint arthroplasty.Methods 40 cases of proximal DVT were collected from May 2007 to October 2016 which were all diagnosed by lower limb venography or sonography.There were 9 males and 31 females aged from 38 to 86 years,average 67 years,and body mass index was from 16.94 to 31.25kg/m2,with an average of 24.3 kg/m2.29 cases of THA patients and 11 cases of TKA patients.The anatomical distribution,size,radiological performance,local physical findings were recorded and multivariable analysis was performed to evaluate the relationship between distribution of proximal DVT and related parameters including age,gender (male/female),side of leg(left/right),surgery type(knee and hip),preoperative diagnosis(femoral neck fracture/other disease),time of diagnosis with DVT (during hospitalization/after discharge).Results Among 40 proximal DVT cases,31 cases diagnosed by phlebography and 9 cases were diagnosed by ultrasound.2 cases were isolated proximal DVT while 38 cases connected with distal DVTs.9 cases of blood clots in the proximal and distal thrombosis connected discontinuously.There was no isolated proximal DVT in TKA group and 10 cases (90.9％) of blood clots in the proximal and distal thrombosis connected continuously while there were 2 cases (6.9％) isolated proximal DVTs in THA group and 21 (77.8％) of blood clots in the proximal and distal thrombosis connected discontinuously,and there was no statistic significant difference between the two groups.The average length of proximal was 8.85±9.3 1cm (range from 2-35cm) with 5.0±2.05 cm in TKA group and 10.31 ± 10.55 cmin THA group.A significant difference was found between the 2 groups (P=0.014).13 cases located in femoral veins and upper venous region which were all from THA group.There was a significant difference in the distribution between surgery type and preoperative diagnosis.However,there was no significant difference between other potential factors and distribution of proximal DVT.25 cases accepted the evaluation of symptom of DVT before scanning.However,no significant difference were found in edema,VAS score,Homans sign,Neuof sign between 9 TKA and 16 THA cases.Conclusion Proximal DVTs after knee and hip arthroplasty are more preferred to connect with distal DVT continuously.Surgery type and preoperative diagnosis have a significant effect on the distribution of proximal DVT.Proximal DVTs in THA and patients with preoperative femoral neck fracture could be more easily involving femoral veins and upper parts.