The invention discloses a new energy vehicle power battery cooling system used for solving the temperature raising problem of an existing battery pack. The system comprises battery cores and uniform-temperature assemblies, wherein the battery cores and the uniform-temperature assemblies are stacked at intervals. Each uniform-temperature assembly comprises a left shell, a right shell, a liquid guide piece, a liquid inlet pipe and a liquid outlet pipe, wherein the left shell and the right shell are of a symmetric structure, an inner cavity of the liquid guide piece is a cooling liquid channel, the edge of the liquid guide piece is embedded in a connection seam of the left shell and the right shell, glue seams are formed in the periphery of the liquid guide piece, uniform-temperature fields are formed between one side of the liquid guide piece and the left shell and between the other side of the liquid guide piece and the right shell respectively, the two side faces of the liquid guide piece are provided with center holes and spiral liquid distribution slots, the liquid inlet pipe and the liquid outlet pipe are externally connected with a liquid pump and a cooler to form a circulating pipeline, and a cooling medium flowing channel is formed. Flowing speed of cooling media in the uniform-temperature assemblies can be controlled, and the aim of controlling temperature in the battery cores is achieved.