BACKGROUND: The current excitation-contraction coupling model of fast-twitch skeletal muscle fibers cannot completely simulate the excitation-contraction process. OBJECTIVE: To solve this problem, this study proposes an excitation-contraction model of fast-twitch skeletal muscle fibers based on the physiological structure and contractile properties of half-sarcomeres. METHODS: The model includes the action potential model of fast-twitch fiber membranes and transverse tubule membranes, the cycle model of [Formula: see text] in myofibril, the cross-bridge cycle model, and the fatigue model of metabolism. RESULTS: Finally, detailed analyses of the results from the simulation are conducted using the Simulink toolbox in MATLAB. Two conditions, non-coincidence and coincidence, are analyzed for both the thick and thin myofilaments. CONCLUSIONS: The simulation results of two groups of models are the same as the previous research results, which validates the accuracy of models.