[Objective] To explore the correlation between the placement of acetabular prosthesis and prosthesis loosening. [Methods] A retrospective study was conducted on 136 patients who underwent primary total hip arthroplasty through modified Hardinge approach in our hospital from September 2010 to March 2017. After follow-up more than 20 months, the patients were divided into two groups accord- ing to whether the prosthetic loosening happened or not. The univariate comparison and binary multiple logistic regression were done to ex- plore the factors related to prosthetic loosening. [Results] At the latest follow-up, 32 of the 136 patients were diagnosed of prosthetic loos- ening, accounting for 23.53%. Among them, 28 patients were acetabular prosthesis loosening only, and 4 patients were combined acetabu- lar and femoral prosthetic loosening. In term of univariate comparison, the loosened group was significantly older than the non-loosening group (P＜0.05) , in addition the former had significantly greater acetabular abduction angle, bilateral difference of offset, abnormal ratio of acetabular abduction angle and abnormal ratio of bilateral difference of offset than the latter (P＜0.05) . However, there was no significant difference between the two groups in gender composition, BMI, acetabular anteversion angle and abnormal ratio of anteversion angle (P＞ 0.05) . As results of logistic regression, the advanced age (OR=0.248, P＜0.05) , abnormal offset (OR=0.159, P＜0.05) , excessive acetabular abduction angle (OR=0.366, P＜0.05) , and abnormal acetabular abduction angle (OR=0.021, P＜0.05) were the independent risk factor for prosthetic loosening. [Conclusion] Poor positioning of the acetabular prosthesis in THA is related to aseptic loosening. During the opera- tion, the abduction angle and prosthetic offset should be kept in a safe range, which will be beneficial to reduce the incidence of aseptic loosening.