LiFe_1-xMn_xPO₄ (x=0.0, 0.1, 0.2, 0.3) and LiFe_1-xNi_xPO₄ (x=0.00, 0.03, 0.05, 0.07) powders were synthesized in a rotor-stator reactor and the reactor possesses high efficient performances of mass transfer and micro-mixing. The powders are used as cathode materials in the batteries and the battery test system is employed to explore the dependence of electrochemical property on temperature. The particle is in the shape of near-sphere, uniformly distributed and in the particle size of 5~10 μm. The crystallographic evidence demonstrates that the introduction of Mn and Ni does not change the host crystal structure. The powders have favorable electrochemical and high-temperature electrical properties. Particularly, LiFe_0.8Mn_0.2PO₄ and LiFe_0.95Ni_0.05PO₄ exhibit the best performance. At room temperature and 50 _oC, their first charge-discharge specific capacities are 153.2/155.7 mAh/g and 156.4/160.4 mAh/g separately with 0.1 C fixed. The capacity retention ratios are 95.4/96.5% and 93.8/95.0% separately after 100 cycles. On one hand, the rotor-stator reactor makes the obtained particle homogeneously dispersed. On the other hand, it also leads the doping Mn and Ni distributing uniformly in the particle. Both of the two advantages increase the Li₊ ionic diffusion rate and enhance the electrochemical and high-temperature electrical properties of the materials.