Objective In order to clarify the changes in gait level of patient after hip replacement, the variation trend of bone density around the implant was studied. It reveals the influence of gait level in postoperative initial and long-term stages on bone density around the implant, which provides the theoretical basis for postoperative rehabilitation. Methods Based on adaptive bone remodeling theory, a femoral-prosthesis finite element model was developed. The distribution of bone density was calculated using the initial and long-term gait level after surgery as the remodeling parameter. Gruen method was applied to quantify the change of bone density. Results In the postoperative initial stage, obvious variation exists in constant gait and change gait groups. The maximum difference occurs in the low gait group, resulting in the reduce of bone density of 41% in the greater trochanter region, the improvement of gait level promotes the enhancement of bone density in proximal and middle end of prosthesis, resulting in the increase of bone density (47%). Long-term gait recovery is responsible for the enhancement of bone density in the middle and end of prosthesis (2%~9%). Conclusions The research findings provide guidance for the rehabilitation process of patients after hip replacement.