Shape Memory Alloy wires are currently employed in robotics, as actuators. In this paper a new mechanism is designed and modeled for a snake robot by using of Shape Memory Alloy actuators. The robot consists of three links which connected together with two revolute joints, two Shape Memory Alloy wires in order to adduction links of robot and two torsional springs to restore links of robot to their original positions. The robot model is simulated in MATLAB/Simulation. Finally, Dynamic behavior of robot is studied under different inputs.