Soft actuators are a type of smart materials in which structural changes can occur due to external stimulation such as heat and light. In this work, a phase change soft actuator with two-way shape memory effect is considered which microstructure is studied, the mechanical behavior of the matrix polymer is modeled and consequently, the actuator force is calculated. Such artificial muscle actuator consists of 00-50 Ecoflex polymer and alcohol bubble. The field emission scanning electron microscope (FESEM) results determine the bubble size and its distribution in the matrix polymer. It is found that more than 80% of the bubbles are in the diameter range of 100 to 400 ?m, which are almost uniformly distributed in the matrix polymer. This proves the homogeneity and isotropy product and its statistical data are used in the simulations. In order to more accurately investigate the hyperelastic and hyperviscoelstic behavior of the matrix polymer, simple tensile and stress relaxation tests are performed, respectively. Performing the optimization processes on the obtained results in Isight software gives the material parameters for hyperelastic and hyperviscoelastic behaviors of Ecoflex 00-50, The obtained parameters properly predict the behavior of the matrix polymer with a negligible error of less than 3% by the method of sum of square difference compare to that of experimental tests. Finally, the artificial muscle is modeled in Abaqus software and relationships for the force response in terms of its volume with the alcohol volume fraction of 5 and 20 are obtained. The experimental and numerical procedures and the obtained results can be used to predict the force response of different artificial muscles with an arbitrary volume. Keywords: Soft phase change actuators, Two-way shape memory effect, Artificial muscle, Hyperviscoelstic polymer, Force response estimation