Abstract: Flat micro-heat pipe ( FMHP) is one of the most effective approaches for cooling the electronic components under high heat fluxes. It has become the important hotspot and development orientation of modern heat pipe technology owing to high heat conductivity and good temperature uniformity. Recently, great deals of efforts have been conducted by worldwide researchers to investigate the flat micro-heat pipe, and several geometric structures of micro groove have been proposed. This paper mainly summarizes the research progresses of FMHP, including the improvement of configuration and machining, the numerical simulation of heat and mass transfer behaviors, the related experimental observation as well as the fabrication and application of new type FMHP.