ObjectiveTo investigate the incidence of perioperative deep venous thrombosis (DVT) of lower extremities and its risk factors in elderly patients with femoral neck fracture. Methods The clinical data of 4 109 elderly patients with femoral neck fracture admitted between August 2012 and November 2020 and met the selection criteria were retrospectively analyzed. Among them, there were 1 137 males and 2 972 females; their ages ranged from 65 to 101 years, with an average of 77.0 years. The time from fracture to admission ranged from 1 to 360 hours, with an average of 35.2 hours. There were 1 858 cases of hemiarthroplasty, 1 617 cases of total hip arthroplasty, and 634 cases of internal fixation surgery. The preoperative age-adjusted Charlson comorbidity index (aCCI) was 4 (3, 5). Perioperative DVT occurred in 857 cases (20.9%). Univariate analysis was performed on age, gender, body mass index, fracture side, time from fracture to admission, operation type, anesthesia type, blood transfusion, blood pressure after admission, and preoperative aCCI in patients with and without perioperative DVT, and logistic regression analysis was used to screen the risk factors of perioperative DVT in elderly patients with femoral neck fracture. ResultsUnivariate analysis showed that there were significant differences in age, gender, time from fracture to admission, operation type, and preoperative aCCI between the two groups (P<0.05). Further logistic regression analysis showed that age>75 years, female patients, time from fracture to admission>24 hours, and preoperative aCCI>5 were risk factors for perioperative DVT (P<0.05). Conclusion Elderly patients with femoral neck fracture have a higher incidence of perioperative DVT. The advanced aged and female patients, patients with longer fracture time and more comorbidities need to pay special attention to the prevention of perioperative DVT to minimize the occurrence of DVT during femoral neck fractures.