Abstract: According to the designed requirements of UV systems, a low-pass filter was studied and developed on K9 glass substrates with high reflectivity at 254nm and high transmittance in visible spectrum. According to the film designed theory, low-pass interference filter film was obtained by optimizing Needle method. The electron-beam evaporation materials of HfO2 and MgF2 were studied. The splash was solved and the absorption was decreased. By using Kaufman ion source, the film density was improved, the drift of spectral curves was solved and the quality of the film was improved by optimizing the process parameters.