The utility model provides a cotton picking machine. The machine comprises a collector and a picking arm, wherein at least one picking arm is arranged on the collector, and connected with the collector; the picking arm comprises a shell, as well as a drive pulley, a driven pulley and a belt which are driven by a motor; an opening formed at one end of the shell is a collecting port; one or more rows of picking needles which are linearly arranged are fixed on the front side of the belt along the vertical direction of the belt; a guiding device ensuring the smooth operation of the picking needles is fixed on the shell on one side of the collecting port along the outer circumference of the driven pulley; and the guiding device extends to the upper side of the collector in the shell along the rotating direction of the belt, and the tail end of the guiding device is provided with a cotton separation plate. The cotton picking machine has the advantages of simple structure, easiness for operation, lightness and flexibility, good collection effect, high picking efficiency, low manufacture cost and the like, and is suitable for industrial production.