In applications of shape memory alloys (SMAs) as actuators and vibration isolation devices, understanding of the nonlinear hysteretic response of SMAs is important. The thermomechanical response, especially the pseudoelastic behavior of Ni-Ti SMAs at various annealing temperatures is investigated. The 2-D numerical model of the SMAs is proposed to predict the thermomechanical behaviors of SMA thin film. The methodology to attenuate vibrations of a host structure by using an SMA film is numerically demonstrated. For the damping enhancement, the structure with SMA films bonded onto it is numerically modeled and the effectiveness of SMA on passive vibration isolation is investigated.