Based on the mathematical model of light intensity distribution in multi-beam interference field,the patterns have been calculated and stimulated respectively for two beams,three beams and four beams interference exposure,in the case of having incidence angle errors and unequal intensity of each beam. The stimulated results have been analyzed and compared with that in ideal situation. The study results show that angel deviation of incident beam mainly affects the shape and period of interference pattern,and inequality of light intensity of each incident beam is the main factor that leads to decrease of pattern contrast. The multi-beam interference lithography experiments have been done by using a laser source with the wavelength of 402 nm. Under the conditions of 32 mW laser output power and 16° angle between two incident beams,by controlling exposure dose and development process,the gratings,dots and holes array with the period of about 1.4 μm have been generated by two-beam interference lithography,and the hexagon array with the period of about 1.7 μm have been got by three-beam interference lithography. The results provide some theoretical reference for fabricating micro-nano periodic structures and improving the quality of pattern by multi-beam interference lithography technology.