Abstract: The knowledge of population genetic variation in forest trees is the basis for further genetic improvement. Since the isozyme techniques were used in genetic studies of forest tree population, great progress has been made. This review outlines a rapid development in studies on forest tree population and genetic variation by isozyme techniques and discusses four problems which warrant careful consideration in research work.It is concluded that there are high levels of isozyme variation and limited isozyme differentiation among natural populations in most forest tree species, and isozyme techniques are very valuable for assessing levels of genetic diversity and degree of differentiation in forest trees and there is great potential of thier application to tree improvement programs, especially in China.