The disclosure provides a cleaning brush configured to clean a working channel of the endoscope. The cleaning brush comprises a first joint, a second joint and a plurality of cleaning units, the plurality of cleaning units are sequentially connected, each cleaning unit comprises a cleaning portion configured to be in contact with the working channel of the endoscope, and the hardness of the cleaning portions of at least two cleaning units in the plurality of cleaning units is different. The first joint and the second joint are respectively connected with two outermost cleaning units in the plurality of cleaning units, and the first joint and the second joint are configured to be connected to make a ring-shaped cleaning brush. The cleaning brush is efficient in removing bioburden from the working channel of an endoscope.