The magnetic separating machine is assembled on a sand dredger in which way the cost can be lowered and the working efficiency improved. Dredging depth is from 0 to 30m and  working capacity from 80 cbm/hr to 100 cbm/hr.  The working capacity, depending  on sandiness and water depth, would reach 100 cbm/hr - 150 cbm/hr if bigger bucket chain dredger is used. The extraction ration of iron sand is more than 70%.