<p>In this paper, the deformation and elastocaloric behaviors of filled vulcanized natural rubber are investigated experimentally and theoretically. In the experimental aspect, four types of experiments are performed, including the quasi-static deformation with different peak strains, rate-dependent deformation at various strain rates, elastocaloric effect under rapid tension-rapid unloading deformation mode, and elastocaloric effect under the deformation mode involving rapid tension-strain holding-rapid unloading-stress holding. Experimental results show that during the deformation of filled vulcanized natural rubber, hyperelasticity and viscoelasticity mechanisms occur simultaneously, and the stress-strain responses exhibit significant nonlinearity and Mullins effect. Furthermore, at higher strain rates, the elastocaloric behaviors show a notable dependence on the peak strain. Both the stress response and the adiabatic temperature change increase approximately linearly with the increase in peak strain. However, the coefficient of cooling performance decreases as the peak strain increases. Based on the experimental observations, a viscoelastic-hyperelastic constitutive model considering the internal heat production is developed within the framework of finite deformation. In addition, the Mullins effect is considered to describe the damage and hysteresis behavior in the process of deformation. Employing the lumped analysis of heat transfer, the evolution of the overall temperature of the specimen is obtained. Finally, by comparing the predicted results with the experimental ones, the capability of the proposed model is validated. The proposed model provides a theoretical tool for the design and performance assessment of rubber-based solid-state refrigeration devices.</p>