The invention provides a decomposable fracturing ball seat surface composite coating, a ball seat and a ball seat manufacturing method. The composite coating comprises a micro-arc oxidation ceramic coating, a hard coating and a high-temperature-resistant polymer coating, the micro-arc oxidation ceramic coating is coated on the surface of the ball seat, the hard coating is coated on the surface of the micro-arc oxidation ceramic coating, and the high-temperature-resistance polymer coating is coated on the surface of the hard coating. The manufacturing method is simple, convenient, feasible and high in operability. The decomposable fracturing ball seat has high corrosion resistance and erosion resistance in a wellhole. In addition, by the manufacturing method, the ball seat is protected well without having impact on mechanical performance and decomposing characteristics of a base material of the ball seat, and close combining among the coatings and between the coatings and a substrate can be realized.