A wide-bore 5 T NbTi superconducting magnet,for magnetic separator,with an operational current of 106 A is designed and fabricated. This magnet with a φ60 mm room temperature bore is installed in a vacuum cryostat and immersed in liquid helium.A two-stage 4 K Gifford-McMahon (GM) cryocooler is used to maintain the cooling shield at 70 K and the condenser at 4 K in order to achieve the zero vaporization loss of liquid helium. The cooling power of the GM cryocooler is 1.5 W.In this paper,the design,heat leakage,stress analysis,quench protection characteristics and preliminary test results are presented.