Objective To acquire the skeletal-muscle抯 stress-strain constitutive equation with various strain rate. Methods In the base of hill's three factors muscle model,this paper uses the method of differential coefficient and linear approach.Results When the strain rate lel≤1,the skeletal-muscle's constitutive equation is different to various strain rate;when the strain rate lel>1,the skeletal-muscle's constitutive equation couldn't be influenced by various strain rate. At the same time,when lel≤1,the influence of the strain rate to the stress is continuously decreasing with the strain increasing.Conclusion The acquired constitutive equation is helpful in using finite method analysing the skeletal- muscle's stress condition with various strain rate.