Abstract:Magnesium diboride (MgB2), which has the great technology advantage at 20-25 K and 1-3 T, is a promising material compared with other metallic superconductors and high-temperature superconductors due to its low cost raw material and without liquid helium. In order to meet the requirement of pratical applications, it is necessary to increase the superconducting properties of MgB2, so the flux pinning properties and intergrain connectivities have become the focus of researchers. In this work, MgB2 bulks with graphene, graphene-acetone solution, graphene coating B doping were synthesiszed and the microstructure, critical current density, flux pinning properties were studied systematically. The critical current density by graphene doping directly got significant enhancement at low field. However, the superconduting properties for samples synthesiszed by solution process and coating method did not improved obviously due to the oxidation decreased the activity of B powders.