Heat management has become one of the key techniques for diode pumped solid state laser′s (DPSSL) performances, such as compact, plug-in efficiency and beam quality. The heat management technology for DPSSL based on low-melting-point Gallium alloys phase change material (PCM) is studied. Experimental result proves that, compared with air-cooled heat radiator, PCM heat radiator can extend laser working hours to six times longer, decrease cooling power to 46% and radiator′s volume to 53%, and improve the plug efficiency from 3.02% to 3.77%. Furthermore, the finite element software ANSYS has been used to simulate the temperature distribution of PCM radiator. The simulated result indicates that PCM has advantages such as low cooling power and small volume. The results provide the theoretical and experimental basis in laser heat management using liquid metal, and has important engineering application value.