Abstract: Supersonic molecular beam injection (SMBI), a plasma fueling technology developed by the Southwestern Institute of Physics with independent intellectual property rights, has been widely applied in multiple Tokamaks due to its high injection speed and excellent directivity. This paper develops and tests a dual-phase (liquid/gas mixture) particle injection system for SMBI, aiming to improve beam focusing performance through low-temperature cluster formation, thereby achieving more precise fueling and plasma density control in fusion devices. To address the limitations of conventional liquid nitrogen cooling, which suffers from non-adjustable temperature and inability to meet the cryogenic conditions below 30 K required for stable cluster formation of light-element gases such as hydrogen and deuterium, this work innovatively integrated a Gifford-McMahon type helium refrigerator with a conventional SMBI system. This integration enabled precise, remotely controllable temperature regulation of the injected gas over a wide range from 24.5 K to 325 K with a control accuracy better than ±0.1 K. The main body of the system employed a transition copper base to achieve thermal coupling between the cold head and the injector, with a coiled copper tube structure for efficient cold transfer. The temperature control system used a PID controller to adjust the heater power, dynamically balancing the heating power against the cooling power of the refrigerator to achieve closed-loop temperature control. On an offline test platform, the system achieved a vacuum pressure of 6.4×10⁻⁵ Pa, a minimum temperature of 24.5 K, and a maximum temperature of 324.96 K, all meeting the design specifications. The cooldown to the minimum temperature took approximately 45 min, while the warm-up to 100 K took about 80 min, providing engineering references for subsequent device integration. Using multiple visualization diagnostics, including a standard camera, a high-speed camera (operated at 3 000 fps), and a schlieren system, the formation, evolution, and stabilization processes of a liquefied hydrogen beam were observed for the first time in a fusion-related SMBI scenario under experimental conditions of 30 K and a hydrogen pressure no less than 1.3×10⁶ Pa. Combining the results of the three diagnostic methods confirm the generation of a liquid/gas dual-phase hydrogen beam. This system is fully functional and meets all performance requirements, thereby establishing the key technological and experimental foundation for low-temperature cluster injection on fusion devices to achieve more precise fueling and plasma density control. Future work will include the introduction of Rayleigh scattering diagnostics, system reliability studies, and experimental exploration of injection conditions with coexisting gas and cluster phases in the temperature range of 40-77 K, aiming to further improve the comprehensive understanding of the phase-state composition of the beam.