Abstract: Metal-semiconductor-metal (MSM) ultraviolet (UV) devices are widely used in UV sterilization detection, optical fiber communication, missile tracking, space exploration, and so forth. In this study, a 3D-MSM device based on AlN is designed according to on the traditional MSM ultraviolet device. By designing 3D-MSM devices with different etching depths, the influence of performance parameters of 3D-MSM devices with different etching depths on device performance was established and analyzed using the APSYS simulation software. The results of the simulation show that the photoelectric performance of the etched 3D-MSM device exhibited a certain performance improvement compared with the traditional MSM device because the introduction of the 3D structure increases the electric field strength between the electrodes, changes the migration path of photogenerated carriers in the MSM device, improves the collection efficiency of photogenerated carriers, and increases the photoelectric performance of the device.