The invention provides a double-wire printing head of a 3D printer and a switching control method of the double-wire printing head. The technical problem that when an existing double-wire printing head carries out printing, two printing heads interfere with each other is solved. The double-wire printing head comprises a wire feeding device and two printing head bodies. The wire feeding device comprises a wire feeding mechanism and a switching mechanism. The wire feeding mechanism comprises a wire guiding pipe base, a left wire feeding pressing wheel, a right wire feeding pressing wheel, a drive wire feeding wheel, a wire guiding pipe, a fixing plate, a pre-tightening spring and a wire feeding motor. The switching mechanism comprises a rotating plate, a switching connecting rod, a push rod and two pressing wheel swing arms. The external force is exerted on the push rod so that the push rod can move, the push rod drives the switching connecting rod to rotate in the moving process, the switching connecting rod exerts force on the rotating plate in the rotating process so that the rotating plate can rotate, and therefore one printing head body inclines, and the other printing head body is upright. In the vertical printing head body printing process, the other printing head body and the printing head body performing printing are not located on the same plane due to inclination, and accordingly the two printing head bodies do not interfere with each other.