With the rapid development of optoelectronic detection technology, deep ultraviolet detection has been widely applied in various fields, including ultraviolet communication, missile warning, missile guidance, and discharge detection. The intensity of solar radiation near the ground within the 280~300 nm range increases exponentially with shorter wavelengths, and thus the response of ultraviolet detectors in visible and infrared wavelengths cannot be neglected. Although scholars at home and abroad have conducted some research on ultraviolet filters, there are few reports on deep cutoff filters with a center wavelength of 225 nm. Therefore, this paper describes the design and development of a deep cutoff filter utilizing a combination of metal and dielectric materials.First, we investigated the design theory of induced transmission filter and selected metal Al, UV-SiO₂, Al₂O₃, and AlF₃ as the film materials. By depositing single-layer of UV-SiO₂, Al₂O₃, and AlF₃, the optical constants of the three dielectric materials were obtained by using the whole spectrum fitting method. To obtain high-quality Al film, multiple experiments were conducted to separate boron nitride crucibles from copper crucibles, reducing thermal conductivity so that the Al film deposition rate climbed faster and more stably. Considering that Al film oxidizes when exposed to the atmosphere, a UV-SiO₂/Al/UV-SiO₂ symmetric film structure was designed and deposited. The ellipsometry parameters of this symmetric film structure were measured by using the ellipsometry method. By establishing an ellipsometry analysis model, the optical properties of the Al film were described using a general oscillators model combined with Tauc-Lorentz oscillators and Drude oscillator, allowing the optical constants of Al film be fitted and obtained. Based on the theory of induced transmission filter, a UV filter was designed using UV-SiO₂ and Al, with an anti-reflection film designed on the back side using Al₂O₃ and AlF₃. The final designed UV filter exhibited a peak transmittance of 33.21% at 225 nm, a half wave width of 28 nm, and an average cutoff depth of 4.7 OD from 280 nm to 1 200 nm. This design effectively collects UV signals, shields background interference caused by background spectral radiation during UV detection, and improves the accuracy of the UV detection system. Subsequently, a filter film sample was prepared based on the predetermined deposition process.Testing the spectral curve of the filter film sample revealed that the center wavelength of the test spectrum shifted towards the longer wavelength region compared to the design spectrum. After analyzing the influence of the metal layer on the spectrum and incorporating the tested spectral results, it was determine that the primary source of film thickness error lay in the dielectric layers. Then, we analyze the film thickness error through inverse fitting and investigate the reasons for the error in the dielectric layers. By increasing the crucible and allocating the film thickness reasonably, the prepared filter sample exhibited good consistency with the designed spectral curve, but there were still differences in peak transmittance and bandwidth. Considering that the rough surface of the thin film generates significant scattering losses in the ultraviolet band, atomic force microscopy was used to characterize the surface roughness of the filter. Furthermore, an equivalent absorption layer model was constructed, the optical constants of the equivalent absorption layer were calculated, and the influence of surface scattering on the spectrum was simulated. The findings indicated that the deviation in the spectral curve of the filter film was not only attributed to the random film thickness error in the film layers, but also related to the scattering loss caused by the rough surface of the film.An anti-reflective film was prepared on the back side, and the final prepared ultraviolet filter exhibited a peak transmittance of 31.55% at 225 nm, a half wave width of 28 nm, and an average cutoff depth of 4.4 OD between 280~1 200 nm. According to the GJB2485A-2019 general specification for optical film layers, the sample underwent the corresponding environmental tests, and after these tests, the surface of the film layer showed no defects such as peeling, delamination, cracks, bubbles, etc.Further research will focus on enhancing the transmittance of ultraviolet light and increasing the cutoff depth of background wavelengths.