The cooling rate effect on the grain boundaries of the CaCu3Ti4¬O12 ceramic was investigated in this research. The resistance at the grain boundaries is found to be reduced as the cooling rate rises. The activation energies at the grain boundaries do not change with the cooling rate, suggesting that the conduction mechanism keeps the same in different cooling conditions. There is no significant difference in the permittivity of the samples. The dielectric loss can be lowered by using a smaller cooling rate. These results give clues to comprehend the conductive mechanism of the CCTO ceramic. The variation of the cooling rate may affect the re-oxidation process and cause the changes in electric properties.