Abstract: Developing a position-sensitive microchannel plate (MCP) detector with high position resolution is of great significance for achieving short-lived atomic nucleus mass measurement at the High Intensity heavy Ion Accelerator Facility – HIgh-rigidity Radioactive Ion Beam Line (HIAF-HIRIBL) facility. This article summarizes the commonly employed design schemes for position sensitive microchannel plate detectors, designs the detector configuration required for conducting nuclear mass measurement experiments at the HIAF-HIRIBL facility, develops a prototype, and performs performance tests. The results show that the magnetic focusing microchannel plate detector is capable of attaining good position resolution within a low acceleration electric field; Neodymium-iron-boron permanent magnets can supply the essential magnetic field for the development of the detector; the α source test demonstrates that the best horizontal position resolution ( \sigma _X ) of the prototype is ~0.42 mm, and the corresponding vertical position resolution ( \sigma _Y ) is ~0.84 mm, which meets the experimental requirements. This research has accomplished the optimized design of a position sensitive microchannel plate detector at the HIAF-HIRIBL facility, establishing a foundation for forthcoming experiments on short-lived nuclear mass measurement.