The invention provides a preparation method for a three-dimensional carbon fiber preform interface coating. The preparation method comprises the following steps: (1) mixing polysilazane, a catalyst with a solvent so as to prepare an impregnating solution; (2) placing a three-dimensional carbon fiber preform into an impregnating apparatus capable of being vacuumized and pressurized, and completely impregnating the three-dimensional carbon fiber preform in the impregnating solution; (3) subjecting the three-dimensional carbon fiber preform containing the impregnating solution to heating under normal pressure or in a vacuum, and carrying out drying so as to remove the solvent; and (4) subjecting the dried three-dimensional carbon fiber preform to heating in an atmosphere containing water vapor, or subjecting the dried three-dimensional carbon fiber preform to irradiating with ultraviolet light, and enabling polysilazane to be transferred into ceramic. The method provided by the invention can form a compact ceramic interface coating on the surface of reinforced carbon fiber, so wettability of carbon fiber reinforcement and a ceramic substrate in the process of preparation can be improved; and oxidation resistance of a ceramic based composite material can be increased.