Abstract: The principle of multi-beam laser interference lithography patterns was studied according to the electromagnetic theory. The factors affecting the patterns were analyzed by comparing numerical simulations with experimental results. It is found that multi-beam laser interference patterns can be considered as superpositions of multiple parallel stripes which are cosine distributed. The?beams’ polarization direction, incident direction and phase difference are important factors influencing the patterns, which affect the parallel stripes’ amplitude, location, period and orientation severely.