The research on theconstitutive models of skeletal muscle has great importance to themuscle-skeletal system as well as the whole sports biomechanics.This article reviews the latest achivements in the study onpassive behaviors of skeletal muscle, including linear-elasticmodel, hyper-elastic model and visco-elastic model. These modelscharacterize the passive responses of skeletal muscle by means ofdifferent theories, and give better descriptions of the behaviorfrom different viewpoints. However, due to the limitation oftheory, any model is not perfect, and thus the authors give basicsummary and make comments about shortcomings and applicability ofeach model.