The invention discloses a preparation method for a thermal-shock-resistant metal-based coating. The method comprises: employing a thermal spraying technology to process the surface of a coarsened metal base so as to prepare the metal-based coating, performing thermal processing on the coating and the base, and when the temperature is raised to a constant temperature lower than the melting point of the metal material in the coating, keeping warm for a certain time, so as to enable the coating and the base to have atom dispersion and form a dispersion layer at the combination site. By utilizing the method, the coating and the base are subjected to metallurgical bond, and also residual stress in the coating is eliminated, so that the metal-based coating is relatively compact and the porosity is reduced, thereby improving the bond strength, the thermal shock resistance and the corrosion resistance of the metal-based coating. The metal-based coating is applicable as a protection coating of hot section components subjected to acute thermal cycling and corrosion in industrial field so as to substantially improve the service life of equipment, and has good application prospect and economic benefit.