The invention discloses a polarization property numerical computation method considering photonic crystal surface oxidation film distribution and relates to the polarization property numerical computation method. The polarization property numerical computation method considering the photonic crystal surface oxidation film distribution is aimed to solve the problems that the prior art does not consider the non-uniformity of film thicknesses at different positions, the workload is large, and the speed is slow. The polarization property numerical computation method considering the photonic crystal surface oxidation film distribution includes that step 1, obtaining space electromagnetic field distribution above a photonic crystal through a FDTD numerical simulation method based on known photonic crystal structure parameters; step 2, calculating radiation polarization properties, and using optical elliptical polarization parameters to represent; step 3, calculating Mueller matrix elements, and building a database; step 4, using an apparatus to measure the optical elliptical polarization parameters of the surface of the photonic crystal, calculating the Mueller matrix elements, and comparing with the database to obtain the corresponding photonic crystal surface oxidation film thicknesses and different oxidation film distribution positions. The polarization property numerical computation method considering the photonic crystal surface oxidation film distribution is used for measuring the photonic crystal surface oxidation films.