A new structure, the platelet heatpipecooled leading edge, was proposed for hypersonic vehicle thermal protection. In order to avoid the challenge of modeling two-phase conjugate heat and mass transfer, an approach of modeling the vapor core as a solid thermal conductor with high conductivity was adopted and the effective vapor thermal conductivity was deduced mathematically. Its effectiveness was validated by comparing the wall temperature against experimental date for a conventional heat pipe. The research result indicates that the nickel based alloy IN718, with sodium as the working fluid, is a feasible combination form Mach 7 with a 15 mm leading edge radius.