Exhaustion of high-grade magnetite resources and large demand for iron ore in the rapidly developing steel industry promotes the mining enterprises to exploit low-grade magnetite. Low-grade magnetite with a low content of valuable minerals is hard to be separated with the conventional separation process flow because of its high beneficiation costs. By preconcentration technology, enriching valuable minerals and discarding large amounts of gangue as soon as possible before grinding, low beneficiation costs can be achieved in low-grade magnetite’s beneficiation. After continuous researches and production practices and the development of relevant efficient crushing and separating equipments, preconcentration technology has made great progress: from crushing-dry magnetic separation technology to grinding-wet magnetic separation technology, then to ultrafine crushing-wet magnetic separation technology. Now preconcentration has become an indispensable stage in low-grade magnetite’s beneficiation.