The invention discloses a method for preparing a high-performance single-component polyurethane waterproof coating. A one-step method is adopted in the method for preparing the waterproof coating, namely the waterproof coating is synthesized in one step by adding raw materials into a kettle body according to a proportion. Different from the preparation of the traditional double-component waterproof coating, the method has simple production operation, meanwhile, saves the operations of metering, mixing, stirring and the like in construction and greatly improves the construction efficiency and the safety of construction personnel. The invention adopts the technical scheme that: the waterproof coating comprises 20 to 40 percent of polyether, 15 to 35 percent of isocyanic acid, 10 to 30 percent of plasticizer, 15 to 30 percent of filler, 0.2 to 4 percent of water removing agent, 0.05 to 1 percent of silane coupling agent, 0.1 to 1 percent of ultraviolet resisting agent, 0.1 to 0.5 percent of synthesis catalyst, 0 to 10 percent of reinforcing agent and 1 to 3 percent of defoaming agent. By adopting the technical scheme and the process, the waterproof coating has excellent flexibility, high strength, ultraviolet ageing resistance and the like.