The invention discloses an intelligent height-limiting device and method for an interchange with a buffering function. The device comprises a height-limiting cross bar, supporting bars and a pre-warning control system, wherein the two supporting bars are separately arranged at two ends of the height-limiting cross bar to support the height-limiting cross bar; the pre-warning control system comprises an induction device and a controller, the induction device is arranged on the height-limiting cross bar to induce height and distance of a vehicle which is about to pass through; when the height of the vehicle exceeds the height of the height-limiting cross bar, the controller sends out a pre-warning signal; the height-limiting cross bar comprises a rigid embedding groove and a flexible buffer layer which wraps the rigid embedding groove. The device and method disclosed by the invention can avoid damage of the vehicle and the height-limiting device, and meanwhile, do not hinder rescue vehicles to pass through, and can pre-warn the driver and can snapshot to take the evidence.