The invention discloses a cross wedge rolling die surface nitriding furnace, comprising a nitriding furnace and characterized in that a bottom wall of a liner of the nitriding furnace is a thickened plane arranged on a turnplate; the bottom wall of the liner is provided with wedged ribs arranged at equal intervals and rotatable anticlockwise relative to the wedge corner direction of a cross wedge rolling die placed in; the bottom wall of a furnace cover is provided with a circular opening, the upper end of the liner is provided with a neck in connection fit with the circular opening, and a ceramic ring is arranged between the inner wall of the circular opening and the outer wall of the neck. As the peripheral wall of the liner of the nitriding furnace is provided with the wedged ribs and the liner is rotatable, the pressure of nitrogen relative to the surface of the cross wedge rolling die increases with rotation of the wedge corners such that the wedge corners have higher hardness and the service life of the cross wedge rolling die can be extended; trials show that the hardness of the wedge corners reaches 52 HRC, and the hardness of broadened wedge parts reaches 50 HRC; by using a method according to the invention, it is possible to prevent high temperature thermal deformation of the cross wedge rolling die and improve the precision of rolled shafts.