Abstract: In order to realize the measurement of resonance wavelength of plasma grating, and research the response sensitivity of grating parameters to stress, a new type of stress-sensitive polydimethylsiloxane (PDMS) thin films plasma grating was proposed. Based on the principle of finite-difference-time-domain (FDTD) method, a structural simulation model, that is periodic plasma grating model was constructed. With the help of periodic boundary conditions and applying the stress on the grating, the resonance wavelength was measured by changing the plasma grating parameters, such as period, duty cycle and Au film thickness, and the response sensitivity of grating parameters to stress was studied. Finally, the simulated results were compared with the theoretical values, and the relative error was obtained. The simulated results show that when the grating period is 0.7 μm, the duty cycle is 55%, and the gold film thickness is 0.02 μm, the response to stress is most sensitive. Secondly, the resonance wavelength at different periods obtained by simulation is compared with the theoretical value, and the results are consistent; when the period is 0.7 μm, the wavelength of the resonance peak is 1.251 μm, and the relative error obtained by simulated results and theoretical values is less than 2%, which means the results are more accurate. This method plays an important role in the fields of monochromator, spectrometer, sensor, and so on.