In this article a new nanosecond pulse laser micromachining system has been designed, which consists of laser, mechanical and optical structure, three-dimensional (3D) work platform, and control system. 355 nm ultraviolet nanosecond pulse laser, with 40 ns pulse duration, is chosen as the light source. The repetition frequency can be set from single shot to 100 kHz. Mechanical and optical structures are designed for laser beam focusing. Computer software resolves the graphics. Moreover, control system based on digital signal processing and field programmable gate array is designed to drive the 3D work platform. With the designed system, some processing parameters have been analyzed and optimized in experiments. Some measures are also taken to improve the microfabrication quality and minimize the splashes of the heat-affected zone. Finally, some microstructures are fabricated by the designed nanosecond pulse laser micromachining system. The width of processing line is about 40 mu m with less splashes.