||Optimum control of the PCB surface temperature is very important in achieving high performance and operational reliability of telecommunication equipment with high power density and thermal density. In this study, the performance of a liquid cooling unit with MPCM slurries (called as “MPCM cooled unit”) was tested and analyzed. In addition, its performance was compared with that of an air cooled unit and a water cooled unit. The maximum surface temperature and the index of uniform temperature distribution (IUTD) were introduced to analyze cooling performance. The surface temperature in the unit rack of telecommunication equipment can be controlled properly by using an MPCM cooled unit instead of an air cooled unit. The maximum surface temperature and IUTD of the MPCM cooled unit at the inlet temperature of 19oC were lower than those at inlet temperatures of 25oC and 27oC due to the increases of heat capacity and heat transfer rate. The heat capacity of the MPCM cooled unit increased significantly with the increase of mass flow rate due to high specific heat of MPCM particles with latent heat transfer rate. The cooling performance of the MPCM cooled unit was superior to that of the water cooled unit.