To provide a coating method of a turbine engine component for coating only an inside surface.

This method includes a step of making aluminide-containing gas flow to a passage in the turbine engine component 10 so as to coat the inside surface for defining the passage, a step of taking out the aluminide-containing gas from an opening part of an outside surface 26 of the turbine engine component 10 by making the aluminide-containing gas flow to the passage and a step of making a certain quantity of gas selected from a group composed of argon, hydrogen, the other inert gas and these mixture to the outside surface 26 so as to minimize a sediment of an aluminide coating on the outside surface 26.