The invention discloses an on-line laser processing vehicle for a rail, including a chassis, a vehicle body, a steer-control chamber and a container; the steer-control chamber includes a console, a CCD monitoring system and a drive-switching operating system; a dual driving system and switching mechanism, which with a process-operation driving system, a conventional operation driving system and a switching mechanism, is disposed in the container; the process-operation driving system operates to provide driving power for the laser processing vehicle during laser processing, and precisely controls moving speed and distance of the laser processing vehicle; the switching mechanism operates to implement switching between the conventional operation driving system and the process-operation driving system. The invention ensures accurate processing trajectories of the laser processing vehicle during laser processing; facilitates on-line laser processing of a variety of rails, such as the rails of main line, curved rails, guard rails, switch rails and so on, so that wear resistance of the processed rail is greatly improved, and meets requirements of high-speed and heavy haul trains for wear resistance of the rail.