Abstract: Due to the demands for speed, real-time performance and portability in the detection of chemical components in aerospace fields, developing a miniaturized mass spectrometer for rapid chemical analysis is one of the important directions in online mass spectrometry research. In this study, a coaxial reflection miniaturized time-of-flight mass analyzer, which consisted of an ionization region, accelerating region, lens region and microchannel plate region was first designed using SolidWorks software. The resulting model was then imported into SIMION, an ion optics simulation software, to simulate the ion trajectories. Based on the principle and design features of time-of-flight mass spectrometer, SIMION was used to optimize the overall performance and key influencing factors related to ion modulation and transmission. On the basis of determining the mechanical and electronic parameters of the instrument, a prototype of a coaxial reflection type miniaturized time-of-flight mass spectrometer was successfully developed. The mass spectrometer exhibited a weight of 716 g (without pump), a volume of 187 cm³, a power consumption of 76 W, and achieved a maximum mass resolution of 44, which satisfied the requirements for resolution and miniaturization. A 532 nm laser was employed as the ionization source, and the positively charged ions were accelerated by the electric field with increasing voltage layer by layer. The accelerated ions were adjusted to change the flight direction by means of three-stage ion lenses, thereby achieving the coaxial reflection of the ions. Coaxial reflection involved that the ions are deflected within the field-free drift region, after which they pass through two reflection zones and coaxially return to the field-free flight area. This coaxial reflection effectively extended the flight distance of the ions and realized second-order spatial focusing. Finally, the ions impacted on the coaxially placed microchannel plate (MCP), and the electrons released by the MCP were captured by the anode plate. Furthermore, the mass spectrometer exhibited the capability of simultaneous detecting metallic samples such as copper, iron, aluminum, titanium and nickel. In summary, the developed coaxial reflection miniature time-of-flight mass spectrometer meets the requirements of light weight, small volume, low power consumption and high resolution, thus, it offers significant scientific research value and practical significance, especially for in-situ rapid chemical analysis in aerospace and other field-beployed scenarios.