The nutritional and health value of peanuts has been paid more and more attention, and fresh peanuts, especially high-sugar sweet peanuts are favored by consumers. In peanut quality breeding, the sugar content of kernels has become one of the important targets, and the research on the molecular regulation mechanism of sugar metabolism is of great importance. Peanut sugar content is one of the determinants of peanut quality traits. The sugar content of the high-sugar peanut line DJ was significantly different from that of the conventional line DG. The total sugar, soluble sugar and sucrose content of DJ were 2.4 folds (p-value = 8.38×10-12 < 0.001), 2.3 folds (p-value = 3.64×10-10< 0.001) and 4.0 folds (p-value = 1.71×10-9 < 0.001) than that of DG, respectively. By RNA-seq and KEGG analysis, 3371 differentially expressed genes enriched in 117 pathways were identified, and four of them were closely related to glucose metabolism. Seven main regulation pathway related genes (including SS, FBP, HK, MAN, PFK, GPI and TPSA) and eight derivative related genes (including USP, RHM, GMLS, 2 UGDH, UGE, GLCAK and GALE) as well as a new gene GAE possibly related to sugar metabolism were detected. Out of the identified differential metabolites, sucrose, D-fructose, trehalose, D-mannose 1-phosphate, ADP-glucose, UDP-N-acetylglucosamine and uridine diphosphate glucose, three metabolites sucrose, fructose and trehalose were significantly up-regulated with the difference folds of 1.18, 1.33 and 8.37, respectively. Transcriptome and metabolome combined analysis showed that starch and sucrose metabolism and fructose and mannose metabolism were the key pathways. Sucrose, fructose and trehalose were the main differential metabolites. By qRT-PCR detection of 16 key differentially expressed genes, three genes SS, HK and GPI were up-regulated, while FBP, MAN, PFK, USP, RHM, TPSA, GMLS, 2UGDH, UGE, GLCAK, GALE and GAE were down-regulated, as revealed by the transcriptome analysis. The results of this study could provide reference for further exploring the molecular regulation mechanism of sugar metabolism in peanut.