Recently, the innovation project watermelon and melon cultivation and physiology team of Zhengzhou Fruit Research Institute has made new progress in the metabolism regulation of sugar and organic acid in watermelon fruit. The changes of sugar and organic acid during fruit development were analyzed and the key gene networks controlling the metabolism of sugar and organic acid during the fruit development were identified. These results provided a theoretical basis for watermelon quality breeding, which had important scientific significance for the development of watermelon industry and the improvement of watermelon breeding level in China. The related research results were published in the journals of Horticulture Research and Scientia Horticulturae.