Abstract: The samples La_0.67Sr_0.33MnO₃/（Bi₂O₃）_x/2 were prepared by doping Bi₂O₃ into the La_0.67Sr_0.33-MnO₃ （LSMO） powder, which was synthesized by the sol-gel method. The XRD result indicates that there exists excess metal Bi in the samples. The resistivities of the samples are influenced remarkably by Bi addition. In the doping range of x=0-0.10 mol ratio, the resistivity rises firstly, and then decreases suddenly with further Bi doping. The resistivity for the sample of x=0.10 is lower than that for LSMO by one order of magnitude. Bi doping has completely different influence on MR effect whichis depended on temperature. At low temperature, the MR ratio decreases with increasing Bi doping amount while at room temperature it enhances with a small quantity of Bi addition. The x=0.03 Bi promotes the MR ratio at room temperature from -4.4%to -5.6%.