Abstract: Although heterosis has been widely used in plants and animals breeding,the studies aiming at unraveling its molecular and genetic mechanisms are still in their infancy.With the continuous development of bioinformatics,there are increasing researches on its gene expression number and expression pattern.Due to the differences in parents,there are significant variations in the number and function of the hybrid offspring genes.The hybrid progeny fusion gene expression has the parent-of-origin bias and thus affects its phenotype.The differences in parental imprint lead to the varied traits and functions of the hybrid offspring.This article summarizes the expression of differential genes,fusion genes and imprinted genes in hybrid progenies,in hoping to give a new insight for understanding the molecular and genetic mechanism of heterosis.