With the rapid development of molecular biotechnology, many improved approaches have been provided for studying on the genetic bases of quantitative traits. Many studies paid attention to dissect the genetic bases using different emendatory approaches from phenotypic variation to gene discovery, mainly containing QTL mapping, chemical mutagenesis etc. Especially, QTL analysis was executed for a lot of important quantitative traits. This paper summarizes the development of quantitative genetics, the recent progress on QTL mapping populations and methods, the status of QTL locating and QTG identification, positional cloning, and QTL application in breeding.