Using the two cultivars(Kexin No. 1 and Feiwuruita)of potato,as the experimental material,the interaction between peach aphid and potato was studied under applying potassium condition.The tendency of peach aphid to potassium application and control plants was determined by using the Y-type olfactometer.The results showed that the trend rate of aphid to Feiwuruita was 26% for potassium application and 71% for control plants and that of Kexin No. 1 was 30% and 64%,respectively.Based on the study above,the main volatile content of two potato cultivars was studied by TCT-GC-MS technique under different potassium application conditions. The results indicated that there were four main compounds including in 3-arene,benzaldehyde,limonene and 1,3-cyclohexadiene varying greatly in the two potato cultivars.The four kinds of volatiles contents were significantly higher than those of the control at the dose of 6 g/plant potassium sulphate in the leaves of Kexin No.1,and limonene content was the highest,reaching 2.5 times of the control. However,only benzaldehyde content in Feiwuruita plants was significantly higher than that in the control.The content of jasmonic acid and activity of lipoxygenase(LOX) in potato were determined by liquid-mass technique and colorimetry respectively.It was found that the jasmonic acid content of Kexin No.1 leaves was 0.93 times higher than the control,and LOX enzyme activity was 0.4 times higher after 6 g/plant potassium application.iTRAQ further demonstrated that 6 g/plant potassium application increased the protein expression of LOX.Overall,6 g/plant application of potassium is the optimal amount of potassium fertilizer for the aphid resistance of potato.