[Objective] To evaluate the factors related to proximal femoral nail anti-rotation (PFNA) failure for internal fixation of inter- trochanteric fractures by meta-analysis. [Methods] Relevant literatures were retrieved from CNKI, Wanfang, Pubmed and other databases, and the data were extracted. Review Manager 5.3 software was used for meta-analysis. [Results] A total of 14 literatures were included, in- cluding 11 papers in Chinese and 3 in English, which all were retrospective case-control studies. All patients (2 477 cases) in the litera- tures were treated with PFNA, and followed up for 6 months at least, and 333 patients of them proved of internal fixation failed. The factors related to postoperative failure of PFNA were as follows: fracture stability (OR=20.94, 95% CI: 13.45~32.61, P＜0.001) , fracture reduction quality (OR=9.68, 95%CI: 4.85~19.3, P＜0.001) , tip-apex distance (OR=3.98, 95%CI: 2.71~5.84, P＜0.001) , osteoporosis (OR=2.88, 95% CI: 2.01~4.15, P＜0.001) , lateral wall integrity (OR=5.40, 95% CI: 3.36~8.70, P＜0.001) , complicated with medical diseases (OR=3.10, 95%CI: 1.75~5.49, P＜0.001) , the zoledronate used (OR=0.47, 95% CI: 0.26~0.85, P=0.01) . [Conclusion] Fracture stability, fracture re- duction quality, tip-apex distance, osteoporosis, lateral wall integrity and associated medical diseases are the risk factors for PFNA failure, whereas using zoledronate is a protective factor.