Abstract: Apple stem pitting virus (ASPV) is one of the most important latent viruses that infects fruit trees. Based on the nucleotide sequence of coat protein (CP) gene from 6 Chinese isolates and other isolates from GenBank, the characteristics of genetic polymorphism of ASPV population were analyzed. The within-population and between-population nucleotide diversities of CP gene among different geographical and hosts origins were analyzed with MEGA 4.0. The results indicated that there were not various relativities between the genetic polymorphism and the geographical and hosts origins. The variation of CP gene was located in purifying selection, and the Asian isolates and pear isolates of ASPV had higher pressure of selection. The analysis of DnaSP software showed that ASPV suffered various population dilatation and the dilatation would continue to develop. Therefore, it need further enhance the detection of virus and elimination of virus for seedlings and strictly control the spread of seedlings infected by ASPV. Key words: Apple stem pitting virus; population; nucleotide diversities