The invention discloses a monitor robot capable of moving on a high-way fence. The monitor robot comprises a rail module, a folding module and a stabilizing module. The rail module comprises a rail and a driving device. The rail is mounted on the fence, and the driving device is used for driving the monitor robot to move along the rail. The folding module is mounted on the driving device, and is used for folding and unfolding a camera. By the stabilizing module connected with the driving module, the driving device is limited on the fence and slides along the rail. The monitor robot has the advantages that the problem of incapability of playing back circumstances when overspeed or car accidents happen in regions without cameras or clear cameras is solved; the problems that the distances among the cameras cannot be adjusted automatically, manual adjustment is needed, situations are always changed at accident-prone road segments especially in some special holidays, corresponding monitor shall be dense in these regions, and some road segments do not need dense monitor are solved.