For the purpose of providing a method to estimate the effect of vibration on the optical performance of a burning diagnosis optical system,a numerical calculation method for the misaligned optical system under interference vibration was proposed. Based on the finite element analysis software ANSYS, the physical model of misaligned optical system under interference vibration was developed and the transient dynamic analysis was inspired by a reflector displacement in the vibration response. Then,the dynamic response of the reflector was obtained by transient dynamic analysis. On the basis of the matrix optics, geometrical optics theory and the mechanic vibration theory, the vibration misalignment matrix of planar reflector was analyzed, and the vibration misalignment model was also built. Meanwhile, the method of simulating calculation of misaligned optical system under interference vibration was inferred. Furthermore,an experiment was carried out to validate the method. The results show the the relative error of simulating calculation and experimental data can reach 4.1% and 0.8% in the horizontal and vertical directions,respectively.