The invention relates to a window cleaning device, which comprises a cleaning head, a slide seat mechanism and a control and drive device; wherein, the slide seat mechanism is connected with the cleaning head to ensure the cleaning head to clean the windows in a movable way; the control and drive device is used for controlling and driving the slide seat mechanism; the slide seat mechanism comprises a longitudinal slide seat, a longitudinal guild way, a latitudinal slide seat and a latitudinal guild way. A longitudinal driving motor of the control and drive device actuates a driving pulley which is connected with the longitudinal driving motor to rotate so that a cog belt can move around the driving pulley and a driven pulley to spur the longitudinal slide seat to move along the longitudinal guild way as well as spur a pivot pulley to rotate together with a rotation axis; the latitudinal driving motor actuates the latitudinal slide seat to move along the latitudinal guild way so as to drive the longitudinal guild way to move in latitudinal direction so that free move in both longitudinal and latitudinal directions of the window cleaning device can be realized.