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It has been found that Dy2O3 doping can enhance critical current density Jc, especially at high temperature (10 K to 30 K), without changing the transition temperature Tc or upper critical magnetic field Bc2 of MgB2. However, it is interestingly noted that the irreversibility field µ0Hirr of the MgB2 sample was increased by Dy2O3 doping. In this paper, the mechanism of the Dy2O3 doping on the MgB2 wire was further studied. A series of carbon and Dy2O3 co-doped MgB2 wires were fabricated. The carbon concentrations of these wires were fixed at 2.0 wt. % and the Dy2O3 concentrations ranged from 2.0 wt. % through 4.0 wt. % to 6.0 wt. %. The heat treatment conditions were 675 °C/30 min, 675 °C/60 min, and 675 °C/120 min. The transport critical current density of the co-doped MgB2 wire was doubled at 20 K, which suggests a reduction in the anisotropy of the critical magnetic field induced by Dy2O3 doping. The specific heats of the MgB2 wires were measured to investigate the anisotropy of the critical magnetic field of the MgB2 wires. The field dependence of the critical current densities of the MgB2 wires was measured at 4.2 K to 30 K. The variation in the resistivity of the MgB2 wires with temperature was measured by using four-point method to study the impurity scattering and grain connectivity of the MgB2 sample. The transverse cross sectional areas of the MgB2 wires were observed by scanning electron microscope (SEM).