The invention discloses an anhydride mixing device for ester acid amino oxalic anhydride. The device comprises a rack, a stirring barrel, a stirring device and a support plate, wherein the upper surface of the rack is connected with a motor, the middle of the rack is fixed with a clamping tool, one end of the motor extends into the rack and is connected with the stirring device, the stirring device extends into the stirring barrel, the middle-lower part of the rack is connected with the support plate, a groove is formed in the upper surface of the support plate, the stirring barrel is arranged above the support plate and comprises an inner barrel and an outer barrel, an interlayer is arranged between the inner barrel and the outer barrel, the outer barrel is nested in the groove of the support plate, the right upper part of the outer barrel is connected with a steam pipe, a steam control valve is arranged on the steam pipe, the right lower part of the outer barrel is connected with a water inlet pipe, a water control valve is arranged on the water inlet pipeline, a thermometer is arranged at the left lower part of the outer barrel, and an opening in the inner barrel is a mixed material inlet. The temperature can be effectively controlled, the labor consumption is reduced, and the production cost is reduced.