Peanut (Arachis hypogeal L.) is an important oil crop because of its high protein and oil content.With the increase of cultivated area, China has become the second largest peanut planted country in the world.Early leaf spot also becomes one of the important factors limiting peanut productivity in China, particularly in Liaoning province.Early leaf spot caused by Cercospora arachiddicola Hori.Small chlorotic spots appeared initially on leaflets in 10 days after infection, and then brown to dark brown,sporulating lesions develop into mature in 15 days, the spot surrounded by yellow haloes.Without foliar applications of fungicides, the disease may cause up to 100% defoliation prior to harvest and losses in excess of 50% of potential yield.Although effective chemical control methods are available, their applications are limited because of the pesticide residues and possible existence of fungicide-tolerant strains of the pathogens.Host plant resistance is thus a valuable tool in a disease management program.The main objective of this research was to identify the major cultivars of peanut which were resistance to the leaf spot disease in Liaoning province and to provide the theoretical basis for resistance breeding and prevention field diseases.