Abstract: In order to study the enzymology metabolism in different sweetness melons, the content of sugar, starch and the activities of sucrose-metabolizing enzymes were tested by taking Cucumis melo‘Hetao’and Cucumis melo‘Loulanwang’in growth stage as the materials. The results showed that: both of the two varieties presented a single sigmoid pattern of growth, the growth rate during fruit swelling of‘Loulanwang’was higher than that of‘Hetao’significantly. These two muskmelon varieties had a similar sugar accumulation trend during fruit development, the glucose accumulation was mainly in early stages, and the glucose accumulation in‘Hetao’was significantly higher than that in‘Loulanwang’. In veraison, the glucose content declined and sucrose content increased, the sucrose content of‘Hetao’was higher than that of‘Loulanwang’. The sucrosemetabolizing enzymes co- regulated sugar accumulation. After the veraison of‘Hetao’, the activity of the synthetic direction of sucrose phosphate synthase and sucrose synthase rose, which could be the major reason for sucrose content increase, and the increased activity of sucrose phosphate synthase during the maturation stage was the main reason for sucrose content in the fruit of‘Loulanwang’.