The cylindrical roller bearing is a detachable bearing facilitating assembly and disassembly. The cylindrical roller is in the liner contact with the bearing race and has a large loading capacity.Capatity of carrying large radial and punching loads and applicable to high speed roration.Such bearing is in multiple varied structures including single-row,double-row and four-row ones and mainly applied to a wide range of motors, dynamors,combustion turbines,main shafts of machine tools.Reducing gears,handing machineries and transporters:and the four row cylindrical roller bearing is mainly applied to the rolling mill.