Objective: To compare the clinical efficacy of the direct anterior approach (DAA) and the posterolateral approach (PLA) for total hip arthroplasty (THA) in the lateral decubitus position. Methods: From July to December, 2014, 104 patients randomly divided into two equal groups of the DAA group and the PLA group underwent unilateral primary THA procedures.All procedures were performed by the same surgeon in the Department of Orthopaedics, the Affiliated Anhui Provincial Hospital of Anhui Medical University.General data, perioperative index, postoperative function and radiological evaluation were recorded and statistically analyzed. Results: The patients had an average follow-up of 14 (range, 10-16) months.No significant differences were detected with respect to the operation time, incision length, preoperative Hb concentration and transfusion rate between two groups (P> 0.05 for all comparisons). However, there were significant differences associated with the intraoperative bleeding, postoperative drainage and postoperative Hb concentration in the two groups(P<0.05 for all comparisons). The DAA group showed significant superior outcomes compared with the PLA group in the Harris hip scores [(83.6±7.1) vs (79.8±6.6), P<0.05], WOMAC[ (28.9±6.1) vs (36.1±6.9), P<0.001], and VAS pain scores[ (2.2±0.9) vs (2.9±1.1), P<0.05]at 1 month after surgery. No differences were seen between the study groups in the evaluation of radiography and the incidence of adverse event (P> 0.05 for all comparisons). Conclusions: Compared with the posterolateral approach, the present study shows the exciting results in patients underwent the DAA THA in the lateral decubitus position at early follow-up.The advantages of THA using the DAA include less operative trauma, alleviation of postoperative pain, and faster postoperative rehabilitation. It is a safe, reliable and effective surgery approach.