Abstract: Aiming at the problems of low efficiency to find redundant nodes in Wireless Sensor Network(WSN),this paper considers the situation of different node's sensing radius in actual network and proposes a distributed algorithm of cover set based on pixels of sensing region.The node sensing region is discredited into a series of pixels to find the redundant nodes.Factors that affect the algorithm's accuracy is discussed.Comparative experiments to existing algorithm show that this algorithm will affect the initial cover set slightly,and the redundant nodes can be selected out effectively.