This study explores the effect of robot locomotion with equipping passive ankle joints. The designed bipedal robot consists of two five-bar linkage legs with torsional springs equipped on both ankle joints, which is constructed and elaborated in SolidWorks® environment. Inverse kinematic analysis for legs are computed in MATLAB® to generate the input values of hip and knee motors for robot locomotion. The simulations are conducted in SolidWorks® motion analysis environment with the aims of evaluating and comparing the dynamic walking performances between the robot model with passive ankle joints and the one with active ankle joints. The proposed robot model is expected to perform continuous walking on flat surface in the simulation and the simulation results are analyzed in three categories including contact force between feet and the ground, motor torques, and motor energy consumptions during the locomotion. The results show the robot with passive configuration has more stable walking performance with lower contact force during locomotion. In the meantime, the average motor torques and average motor energy consumptions of passive configuration during simulation are lower than the ones with active configuration.