The invention discloses a rectangular winding wire for a new energy electric automobile motor and a manufacturing method thereof. An adhesive glue layer is arranged on the external surface of a core wire; a corona-resistant insulating layer is arranged on the external surface of the adhesive glue layer; an insulating layer capable of enhancing heat performance and chemical resistance is arranged on the external surface of the corona-resistant insulating layer; and the cross section of the core wire is shaped like an oblong with a round angle. The manufacturing method comprises the following procedures of extruding, annealing, cooling, washing, painting, baking, lubricating and winding. Through the adoption of the method disclosed by the invention, a plurality of insulating layers with different performances are formed on the external surface layer of a copper core through repeated painting and baking, so that a corona-resistant enameled wire with a composite insulating layer is formed; and the corona-resistant enameled wire obtains very good adhesion property and corona resistance; and requirements on corona resistance and temperature resistant grade of a variable frequency motor can be satisfied.