Chaotic secure communication has been a hot topic of the research in communication field recently. Chaotic synchronization is a basis of realizing chaotic communication. The effect of the parameter mismatch degree on the chaotic synchronization in the Chua's circuits is discussed in this paper. The results of this study are that the mismatch degrees of different parameters have different effects on the chaotic synchronization. This is of great use in practice, so different precision elements can be selected according to the effect of the parameter mismatch degree on the chaotic synchronization.