A method is proposed to measure the topological charge of an anomalous vortex beam.A mask is placed before the receiving aperture,and the topological charge of the anomalous vortex beam can be measured through analyzing the intensity distribution on the receiving plane.The analytical expression describing the intensity distribution of the anomalous vortex beams after passing through the mask is derived.Based on the expression,the intensity patterns are obtained through numerical simulating.It is shown that the intensity distribution on the receiving plane is a multi ring pattern,and the number of rings is related to the topological charge of the anomalous vortex beam,but not to the beam order.The results are of great significance to the application of anomalous vortex beams.