A continuous staged permanent-magnet high-gradient magnetic separation device for weakly-magnetic powder is disclosed. The device includes a rack, a feeding port, a concentrate discharging port, a tailing discharging port, an external magnetic pole magnetic yoke, an internal magnetic pole magnetic yoke, a magnetic matrix cylinder, a rotating shaft, internal magnetic poles, external magnetic poles,external magnetic pole armoured arc-shaped permanent magnets, external magnetic pole extruded arc-shaped permanent magnets, internal magnetic pole armoured arc-shaped permanent magnets, internal magnetic pole extruded arc-shaped permanent magnets, and a magnetic matrix. The magnetic separation device provides three stages of stepped separation zones, and magnetic field intensities increase gradually from top to bottom in order. The three stepped separation zones include a high-performance NdFeB-magnetic-source separation zone, a common NdFeB-magnetic-source separation zone and a ferrite-magnetic-source separation zone, and matched magnetic matrix filling ratios are 3-5%, 7-9% and 12-15% respectively. Compared with the prior art, a plurality of difficult problems caused by adopting water as a medium in wet type separation are solved by the device, a complex process for water treatment is omitted, the separation process is simpler, the operation cost is directly reduced, and the deviceis convenient to use and maintain.