Laboratory animals support the life science research. Based on their clear genetic, immune background, mice have been widely used. In the Post-genomics era, a great deal of genetic engineering mouse models, including those transgenic mice and gene targeted mice had been developed to study some a specific gene. However, most human diseases are not controlled by a single gene; besides the environmental factors, multiple genetic factors can influence the development of human diseases. The complex multi-gene traits research in life science put forward new challenges to the laboratory animals. To meet this challenge, scientists have proposed to develop a new mouse resource called the Collaborative Cross (CC) mice. This paper will review the background and character of CC mice, and gives some suggestions for its application.