Purpose The intervention mode of 12-week gait retraining (with the specific aim of changing the habitual running gait) was established to determine the changes of vertical ground reaction force (vGRF), hip/knee/ankle kinematics, dynamics and stiffness characteristics of lower limbs before and after GR running, and to explore the influence of running posture transformation on impact force and lower limb biomechanics. Methods Vicon motion capture system and Kistler 3d force measurement platform were used to collect the ground reaction force and mark point track of 30 runners (15 in the experimental group and 15 in the control group) before and after retraining with minimalist shoes at a speed of 3.33±5％m/s. Results a total of 17 subjects (9 in the experimental group and 8 in the control group) completed the training. After training: 1) the maximum loading rate of both groups decreased significantly, and the maximum loading rate of the experimental group was lower than the control group. 2) the foot strike angle of the experimental group decreased significantly after training, and the plantarflexion Angle and hip joint angular extension velocity increased in both groups. 3) the moment of ankle joint increased in the experimental group, and the stiffness of lower limbs was significantly improved in both groups. Conclusion A 12-week gait retraining (GR) exercise intervention model was established to convert runners who used to rearfoot strike to forefoot strike (conversion rate 78%). Specific on: GR training can effectively avoid the peak of impact force, reduce the maximum loading rate, increase the lower limb stiffness, and thus reduce or even avoid the risk of running injury caused by impact force and may provide a possibility for the improvement of running economy and corresponding energy utilization rate.