The invention discloses a guideway-type three-dimensional crawling robot traveling device with a magnetic attraction positioning function, comprising a belly and castors; a control system is mounted in the belly; a center-of-gravity adjusting device is fixedly mounted in the center of the belly and comprises a spherical shell, a horizontal ring is mounted at two ends of the inside of the sphericalshell, a vertical ring is mounted in the horizontal ring, a disc is mounted in the vertical ring through a horizontal rod, the castors are mounted at four corners of the belly through vertical rotaryrods, each castor includes a rim, planet gears are connected with each rim through inner teeth, the corresponding planet gears are connected with a sun gear through outer teeth, the sun gears are connected with a servo motor through wheel shafts, and the servo motor is connected with the control system through a wire; the four castors for a magnetic robot bear stress evenly and can firmly attractto a guideway, and accordingly, the robot may crawl in the guideway in a three-dimensional space more stably.