Abstract: Micro pulse tube coolers hold significant value for military and space applications. This paper experimentally optimized a miniaturized coaxial cold finger operating at 80 K. The cold finger weighs 77 g, and optimization was conducted on the internal filling method of the regenerator within the cold finger, the charging pressure of the cooler, and the phase shift mechanism of the cooler. When the input power to the cooler was 30 W and the operating frequency was 138 Hz, with a hot-end temperature of 324 K, the lowest achievable temperature of the cooler reached 69.89 K. When the cooler operates in the 80 K temperature range, its cooling capacity at this point is 0.3 W. Under these conditions, the total mass of the pulse tube cooler system is 400 g. The optimization process focused on enhancing thermal efficiency and reducing mass, which are critical for applications where compactness, lightweight design, and reliable performance in extreme environments are paramount. The improvements in regenerator packing, pressure management, and phase adjustment contributed to achieving a lower minimum temperature and a practical cooling capacity suitable for targeted operational scenarios. These advancements underscore the potential of such miniaturized coolers in enabling advanced infrared sensors, electronic cooling, and scientific instrumentation in both military and space contexts, where stringent constraints on size, weight, and power consumption must be met. The results demonstrate a balance between performance and miniaturization, paving the way for further integration into portable or space-constrained systems requiring efficient cryogenic cooling solutions.