Abstract: M625（high-generation inbred line of thick-skinned muskmelon） and M44（high-generation inbred line of thick-skinned muskmelon） were selected as the test materials, the methods of soaking seeds and spraying copper preparations on the leaves were used to study the effect of copper preparations on the main body of muskmelon in different periods.The effects of vine length, stem diameter, maximum functional leaf area, maximum functional leaf node position, maximum functional chlorophyll relative content SPAD value, single melon mass, central sugar content, diseased leaf rate and copper damage index, in order to provide reference for exploring the different of copper sensitivity in different periods of melon.The results showed that the spraying of copper preparations at different times reduced the main vine length, stem thickness, leaf area, chlorophyll content, yield and quality of the two melon materials to different degrees, with the greatest decrease in each index at the seedling stage; the spraying of copper preparations at different times increased the maximum functional leaf nodal position, leaf disease rate and copper damage index of melon to different degrees, and the earlier the spraying of copper preparations the more obvious the copper damage performance.M625 and M44 were the most sensitive to copper preparations at the seedling stage, with the most severe copper damage, followed by the melon stage, and the difference between the seed dipping treatment and CK was not significant.In conclusion, the differences in the effects of copper sprays on the growth index, yield, quality and copper damage indexes of the two melon materials were basically the same, and the order of copper sensitivity was seedling stage＞vine extension stage＞melon sitting stage＞seed dipping.