Abstract: Copy number variations (CNVs) refer to the deletion, insertion, and duplication of genes over 1 kb in length. CNVs were widely found in human and other mammalian genomes. Here, we mainly reviewed the impacts of CNVs on the human diseases, and introduced the general detecting methods for CNVs. We also discussed the potential relationship be-tween CNVs and disease-resistant breeding of animals. Because of the significant effects of CNVs on the resistance and susceptibility of disease, CNVs can be used in the marker-assisted selection, QTL fine mapping, and disease-resistant breeding of livestocks by means of biotechnologies.