The invention provides a preparation method of a nitrogen-doped carbon-loaded platinum-based catalyst for a fuel cell. The preparation method comprises the following steps of preparing nitrogen-dopedcarbon powder, preparing a nitrogen-doped carbon powder polymerization body, preparing a nitrogen-doped carbon-loaded platinum-based mixed solution and preparing a product. According to the method provided by the invention, the utilization rate of a Pt catalyst is greatly improved, the performance and the stability of the Pt catalyst are improved, the proton transmission function is achieved, andthe cost is greatly lowered. According to the technical scheme provided by the invention, an intermittent microwave mode is adopted, so that the reaction temperature can be well controlled, the temperature rise is uniform, and the repeatability is high.