Many human diseases are related to quantitative traits, but it is very difficult to find the genetic quantitative trait loci directly in human subjects, where the quantitative traits dominate. Rats and mice can well complement those shortage, because they have not only good reproduction capability, but also high congenetic genome. Therefore, many researchers have been making use of rats and mice as a kind of model animal to study QTLs controlling human diseases. In this review mapping of quantitative trait loci for some traits on rats and mice was introduced.