FSMAs like Ni<sub>2</sub>MnGa have attracted significant attention over the last few years. As actuators, these materials offer high energy density, large stroke, and high bandwidth. These properties make FSMAs potential candidates for developing Solid-Fluid Hybrid Actuations (SFHA), where the FSMA actuator provides the mechanical energy by the linear reversible displacements. In order to develop effective hydraulic pumps with the FSMA actuators, it is important to study the dynamic behavior in these materials. In this paper, a dynamic model is presented for an Ni<sub>2</sub>MnGa actuator. The Ni<sub>2</sub>MnGa actuator model consists of the dynamics of the actuator, kinematics of the actuator, constitutive model of the material, and reorientation kinetics. A constitutive model is proposed to take into account the elastic deformation as well as the reorientation. Simulations results are presented to demonstrate the dynamic behavior of the actuator.