The invention discloses a body-in-white totally-splicing switching mechanism. The body-in-white totally-splicing switching mechanism comprises a traction mechanism for driving a switching clamp to move, positioning mechanisms are arranged on the two sides of the traction mechanism correspondingly, and the switching clamp moves to the two sides of the positioning mechanism to be clamped by the positioning mechanisms. According to the body-in-white totally-splicing switching mechanism, aiming at the switching mechanism during switching of totally-spliced vehicle types, the totally-spliced vehicle types can rapidly switched to another vehicle type, the requirement of the accuracy of repeated positioning is ensured, the vehicle types share a totally-splicing mechanism, easy and rapid switchingcan be achieved, the positioning accuracy of the switching mechanism is not affected, the body-in-white totally-splicing switching mechanism is often applied to non-standard equipment of an automatedflexible car production line, and good application prospects are achieved.