The invention discloses a double plastic coextrusion die. The double plastic coextrusion die comprises a die body, a transition plate, a rear bracket, a front bracket, a conflux plate, a mouth model,a cooling water jacket and a core rod which are sequentially connected; the die body, the transition plate, the rear bracket, the front bracket and the conflux plate are arranged in equivalent width,and conflux chambers are arranged in the die body, the transition plate, the rear bracket, the front bracket and the conflux plate. Cavities are formed inside the mouth model and the cooling water jacket, a separating piece is arranged at the inlet of each cavity, a plurality of inverted isosceles trapezoids are arranged on the separating piece at equal intervals, and the inlet of each cavity is divided into two parts which are interlaced. The double plastic coextrusion die can make two materials of a double plastic coextrusion hollow pipe uniform in distribution and stable in structure.