Abstract: To investigate the performance enhancement of AlN-based MSM photoelectric devices using three-dimensional (3D) structures with AlN as the light-absorption layer material, a 3D structure was introduced by etching the AlN layer based on the traditional MSM photoelectric device. A 3D-structured MSM device (3D-MSM) was designed and fabricated, and its photoelectric performance was tested and analyzed. According to the test results, the photoelectric performance of the 3D-MSM device was significantly better than that of the MSM device. Specifically, the 3D-MSM device with an etching depth of 1 μm achieved a photoresponsivity of 8.2 mA/W, which is a 26.1% increase in photoresponsivity, 52% increase in photocurrent, and 26.7% reduction compared with the MSM device. In addition, the 3D structure devices array was used to prepare and test the ultraviolet detectors, and the device array had good imaging functions for different shapes and patterns.