The (1-x) La_ 0.67 Ca_ 0.33 MnO_3 (LCMO)+x Cr_2O_3 composites were synthesized by a new liquid phase method. The XRD and SEM measurements reveal that few Cr_2O_3 were soluble in the LCMO structure and the lattice constant of LCMO almost did not change, while most Cr_2O_3 were distributed at the grain boundaries or on surfaces of the LCMO grains. In resistivity versus temperature measurements, a metal-insulator transition was observed when x<0.20. The resistivity increases and the metal-insulator transition temperature decreases with the increasing content of Cr_2O_3.A random resistor network (RRN) model was used to simulate the transport property of the mixture samples. The simulation results agree with the experimental observations. The results show that the method is reasonable for understanding the electronic transport of the composites of the maganite. The (1-x) La 0.67 Ca 0.33 MnO 3 (LCMO) + x Cr 2 O 3 composites were synthesized by a new liquid phase method. The XRD and SEM measurements reveal that few Cr 2 O 3 were soluble in the LCMO structure and the lattice constant of LCMO almost did not change, while most Cr 2 O 3 were distributed at the grain boundaries or on surfaces of the LCMO grains. In resistivity versus temperature measurements, a metal-insulator transition was observed when x <0.20. The resistivity increases and the metal-insulator transition temperature decreases with the increasing content of Cr 2 O 3. A random resistor network (RRN) model was used to simulate the transport property of the mixture samples. The results show that the method is reasonable for understanding the electronic transport of the composites of the maganite.