By the method of direct wet process which has been developed in our laboratory, the high purity BaTiO3 powders could be synthesized from the room temperature to 90$^{circ}C$ according to particle sizes. For to detect the PTCR effects, Sb2O3 wasdoped in the BaTiO3 powders which had been prepared on above method. As the results, the PTCR effects were in creased with the decreasing grain size of BaTiO3 powders.