Abstract: In this paper,optimization design and preparation of the medium-wave infrared broad-band short-wavelength pass filter was investigated,and design principles and methods was discussed.The equivalent-index method was used to design the filter and thicknesses of some chosen films were optimized.The short-wavelength pass filter in medium-wave infrared band was designed,which shows an average transmittance ratio is more than 90% at wavelength region 2300~4700nm and an average transmittance ratio is less than 1.00% at 5000~6300nm.The filter was prepared successfully by using a convergent infrared optical system and a plasma assistant deposition technology.The result shows that make use of the method of optimizing some chosen films,the film system is simplified and it is convenient to monitor the film thickness.