Abstract: Willow (Salix) is an important wide-leaved tree species worldwide. Genetics study of the genus Salix was undertaken early because the genus is very heterogeneous, comprising more than 500 species and distributing broadly in every continent except Australia and Antarctica. This paper reviews the literature about Salix on genetic diversity of characters, population genetics, genetic identification, construction of genetic linkage maps and quantitative trait loci. On the basis of the characters of forest trees and willow biology traits, Salix could be a perfect model species for forest tree genetics, so genetics research into Salix should be given special attention.