The invention relates to a thermal protection method for a scramjet engine fuel injection supporting plate by the utilization of transpiration cooling. The method includes the following steps that (1), high temperature resistant material is used for manufacturing the injection supporting plate of a multi-tiny-hole structure, and a fuel pipe of a scramjet engine is communicated with the injection supporting plate; (2), by the utilization of the process that fuel leaks through holes of the injection supporting plate of the multi-tiny-hole structure, and heat convection is performed forcibly, so that the heat on the surface of the injection supporting plate is taken away; (3), it is utilized that the fuel leaks through the surface of the injection supporting plate to form a thin layer, so that main flows are prevented from performing heat transfer on the injection supporting plate. The multi-tiny-hole structure is manufactured on the injection supporting plate material, the concept of transpiration cooling is used, the fuel serves as a cooling agent, so that strong heat convection happens between the fuel and the injection supporting plate in the process that the fuel flows through the injection supporting plate, meanwhile, the fuel forms the thin layer on the surface of the injection supporting plate, heat transfer between the high temperature main flows and the surface of the injection supporting plate is obstructed, thermal protection on the injection supporting plate and particularly the front edge part of the injection supporting plate is achieved, and the injection supporting plate is prevented from being ablated and damaged. The thermal protection method can be widely applied to thermal protection performed on various ramjet injection supporting plate structures.