To study the characteristics of displacement response for a V-shaped electrothermal actuator， considering that the material parameters are affected by temperature nonlinearity and discontinuous boundary problems in the mathematical model， the characteristics of displacement response for the V-shaped electrothermal actuator were studied in theory， simulation， and experiment. First， an electro-thermal-mechanical coupling model of a V-shaped electrothermal actuator was established by introducing updating functions of a material parameter related to the temperature. Expressions for the temperature and transient displacement of the V-shaped electrothermal actuator were obtained using the improved Chebyshev spectrum method to solve the constructed coupling model. Then， a finite element simulation and theoretical analysis of the temperature and displacement of the V-shaped electrothermal actuator were performed to verify the correctness of the model. Finally， an experimental platform for the transient displacement response of the electrothermal actuator was constructed. The experimental results of the displacement response for the V-shaped electrothermal actuator under constant voltage excitation were compared with the theoretical and simulation results. The displacement response of the V-shaped electrothermal actuator under a periodic square wave voltage was tested. The test results reveal the following： the V-shaped electrothermal actuator performs periodic variation after a certain amount of time. The cycle is identical to that of the square wave voltage. Under similar conditions of other parameters， the average displacements of the electrothermal driver under the action of the peak-to-peak 14 V periodic square wave voltage are 20 µm. Furthermore， the average displacements under the action of the peak-to-peak 7 V periodic square wave voltage are 28 µm. The displacement variation of the electrothermal actuator under the action of a periodic square wave voltage with a frequency of 50 Hz is 7 µm larger than that under a frequency of 100 Hz. The mean displacement is approximately equal. However， the variation range of displacement is negatively correlated with frequency.