It has been confirmed that the pathogenic fungus of pear canker has the same morphological characters in endostroma with the pathogenic fungus of apple canker(Valsa mali Miyabe et Yamada).Howerer,there are significant difference in many other characters between the two pathogenic fungi,such as morphology of exostroma,colony color,texture,structure,esterase isoenzyme bands and host-parasite reactions It was demonstrated that the diseases could be caused by cross-inoculation with two pathogens in indoor experiment,but not in outdoor experiment.Further test with the two pathogens isolated respectively from infected plants showed the above characters were kept steadily and not be influenced by host changing.It is therefore,concluded that the pathogenic fungus of pear canker disease is a new variety Valsa mali Miyabe et Yamada var.pyri Y.J.Lu,var nov et.