Abstract: Numerical simulations were used to simulate the temperature of liquid-jet at periodic boundary condition. Mainly was studied the temperature of the SMA effected by exit velocity, nozzle-to-surface spacing and jet periods. It is found that the temperature on the surface of SMA actuator also has a fluctuation with the periodic boundary condition, and the temperature wave amplitude increases with the increasing of exit velocity,jet periods,with the decreasing of the nozzle-to-surface spacing.