Due to the common grab dredger is not suitable for maintenance dredging in narrowness,shallowness and danger of upper stream river,a special dredger has been developed.The dredger integrates grab bucket,hoe shovel and steel harrow into a whole body,which is suitable for sandy gravel waterway maintenance.The performance analysis of positioning system,dredging equipment and Auxiliary dredging system is done.Based on the construction data,the social benefit is evaluated.