The invention discloses a CRTSIII type track slab profile measurement device and a control method thereof, and belongs to the technical field of track slab detection. The device comprises a three-dimensional measurement system, a transport plate trolley and a measurement stand. The three-dimensional measurement system comprises a three-dimensional laser scanner, a measurement holder, a rotating device, a service bridge and a PC console. The service bridge is composed of a shear shank, traveling wheels, a reduction unit, a locking device and a PC console. The transport plate trolley is composed of a track battery cart, limiting posts and jacks. The measurement stand is composed of a work platform of the rectangular structure, a sensor, a signal controller and supporting posts. The problems that the present CRTSIII type track slab is low in accuracy and slow in measurement and requires artificial intervention in the detection process and the detection data cannot be uploaded in real time can be solved so that the detection efficiency can be greatly enhanced, the device is suitable for the novel assembly line work method of the track slab, and a solid foundation can be laid for worldwide popularization of the CRTSIII type track slab independently researched and developed by China.