In order to forecast and warn of space weather， the disturbances of solar-terrestrial need to be monitored. Extreme Ultraviolet （EUV） filters can remove unwanted radiation， and they are an important part of the Extreme Ultraviolet Imager. In order to optimize the transmission of EUV filters at 17.1nm， we chosen the material and thickness of EUV filters at 17.1 nm based on the Lambert-Beer law by theoretical calculation and software simulation. First， the release layer and metal thin-film were deposited by thermal evaporation， and EUV filters with nickel-mesh supported were successfully manufactured. After testing， the transmission of the filter whose surface is smooth and flat without obvious pinholes is about 43.81% at 17.1 nm. Next， in order to illustrate the effect of the oxide layer on the transmittance， the filter sample was measured by spectroscopic ellipsometry to obtain the thickness of the oxide layer at different placement times， and the roughness was measured to optimize and simulate the transmission of the filter. The thickness of the oxide layer and the roughness of the sample were fitted by IMD， and the layer thickness was adjusted to achieve the curve closest to the actual measured value. Experimental results indicate an excellent agreement between the measured and simulated values， and the absolute error of the transmittance of the EUV filter is only 1%. This study provides preparation methods and improvement ideas for EUV filters， and has important practical significance in space exploration.