Abstract: Taking Korla pear trees and orchards with different degrees of disease as test materials,the N,P,K content in the phloem of annual branches and the N,P,K content in the soil were measured.The Korla pear rot pathogen was inoculated on N,P,K media with different concentration gradients.Colony morphology,growth rate,and spore production were observed and recorded.The correlation between N,P,K content and disease degree was analyzed.The relationship between N,P,K and Korla pear rot disease were studied,in order to provide reference for the comprehensive prevention and control of Korla pear rot disease.The results showed that different concentrations of N,P,K had an impact on the growth of the colony.The growth rate of the fungus decreases with the increase of the N content.With the increasing of the P and concentration,the growth rate of the pathogens first increases and then decreases.The incidence of Valsa canker of Korla pear was negatively correlated with soil K content and tree K content,and positively correlated with soil and tree N/K,P/K ratio.The higher the ratio of N/K,P/K,the more serious the occurrence of Valsa canker.Orchard management should increase the application of nitrogen and potassium fertilizers,and pay attention to the application of organic fertilizers,which can reduce the incidence of Korla pear Valsa canker.