Abstract: Al-0.4Mn alloy was modified by B and rare earth element Y, Sm and Ce. The influence mechanism of modified elements on the electrical conductivity of the alloy was studied. The results show that Al-0.4Mn alloy could be effectively modified by right content of B or Y element when the single element was added into the alloy, and the largest electrical conductivities of alloy were 26.13, 25.32 MS·m^-1, improving by 6.80% and 3.47% that of unmodified alloy, respectively. Ce and Sm elements would reduce the electrical conductivity of the alloy. The composite modification of 0.3wt% B +0.5wt% Y had a better effect on improving the electrical conductivity of the alloy; the electrical conductivity was 26.64 MS·m^-1, improving by 8.9% that of unmodified alloy. When the alloy was composite modified by 0.3wt% B +0.5wt% Y, the precipitated AlB₂ by borylation adsorbed Mn and Y at the same time, promoting the precipitation of doped borides and Al-Mn-Y phase; part of the Al₃Y formed by Y had a certain adsorption effect on Mn, which further reduced the solid solution amount of Mn in the aluminum and lattice distortion of the substrate, and significantly improved the electrical conductivity of the alloy.