A micro-channel phase-change heat sink has been developed for cooling high power continual laser diode (LD) based on coupling of boiling-cavitation in micro-channel and field synergy principle. The electron-optic conversion efficiency, output wavelength and the relation between input current and output power are measured experimentally when LD output power changes from 0 to 100 W. The cooling refrigerant is R134a. The thermal resistance of heat sink is measured as 0.211 ℃/W when the magnetic drive gear pump is operated at 23 r/s motor speed. Comparing with the previous heat sink, the thermal resistance of the micro-channel phase-change heat sink based on field synergy principle decreases significantly.