To provide a method for applying fiber/matrix interface coatings cost-effective and efficient as compared to a coating method using CVD without the need for a complicate processing step.

The method for applying an interface coating to at least one surface of a fiber-based substrate includes a step (step 10) to place the fiber base substrate in a liquid tank containing a sizing agent, ceramic powder and arbitrarily at least one substance selected from a dispersing agent, a deflocculant and a surface wetting agent, a step (step 12) to perform the heat-treatment of the substrate coated by the former step, and a step (step 14) to impregnate the substrate with a matrix material. A process having high cost-effectiveness and efficiency can be realized by introducing an interfacial coating material in the sizing operation carried out usually before the impregnation of the matrix material.