In this work,a water cooling system based on the micro heat exchanger with sintered cutting copper fibers is put forward to meet the requirements of heat dissipation for the high power LED.The effects of different porosities and different composite forms of sintered cutting copper fi bers on the chip′s surface temperature and the pressure drop between the import and export of the micro heat exchanger are experimentally investigated. As for the micro heat exchangers with simple sintered cutting copper fibers,the results of experiment indicate that the micro heat exchanger with the porosity of 80% presents the best performance of heat dissipation on the chip′s surface temperature,whereas the micro heat exchanger with the porosity of 75% ha s the largest pressure loss between the import and export at the same condition of inlet flow rate.As f or the micro heat exchangers with composite forms of sintered cutting copper fibers,the results of experiment sho w that the heat exchanger with the composite-porosity of 80%－85% has the best heat dissipation performance on the chip′s surface temperature,while the micro heat exchanger with the composite-porosity of 75%－80% has the large st pressure drop between the import and export at the same condition of inl et flow rate.