The invention relates to cleaning and spraying equipment in a cleaning and spraying robot for a wall surface. A cleaning and spraying stretchable arm for a wall surface mainly plays a role in enabling a cleaning part in the robot to be freely compressed and separated from the wall surface in the automatic equipment. In order to realize the purpose, two slide rails and a rack are installed on the rectangular stretchable arm; four slide blocks and a control motor are installed on an aerial working basket; after the slide rails penetrate in the slide blocks, the rectangular stretchable arm and the aerial working basket form a whole; and the rack on the rectangular stretchable arm is closely engaged with a gear of the control motor, and the rectangular stretchable arm is made to freely displace back and forth by controlling the positive rotation and the reverse rotation of a motor through an inductor on a cross rod. Therefore, the cleaning or spraying equipment connected to the wall surface end of the rectangular stretchable arm is capable of freely escaping a bulged object with a certain height on the wall surface and keeping a set distance with the wall surface.