The invention relates to the technical field of power electronics, in particular to the field of transformers. A cooling water unpowered self-circulation new energy transformer cooling system comprises a water flow channel arranged inside a transformer main body. The water flow channel is provided with a water inlet and a water outlet, and the water outlet is arranged above the transformer main body. The cooling water unpowered self-circulation new energy transformer cooling system further comprises a fluid radiator helping fluid to circulate to radiate heat. The fluid radiator is arranged on top of the transformer main body, the water outlet is connected with an inlet of the fluid radiator, and an outlet of the fluid radiator is connected with the water inlet of the water flow channel. The cooling water unpowered self-circulation new energy transformer cooling system is simple and reasonable in structure and achieves self-circulation and utilization of cooling water of the transformer main body by arranging the fluid radiator on the top of the transformer main body.