Abstract: For the purposes of detecting the maturity of small watermelon and real-time monitoring its internal quality during the growth, this paper studied a variety of basic information in constantly changing circumstances along with growing days of mini watermelon fruit Jingxiu. During the growth, the majority of the small watermelon basic information changes follow certain regularities and some indicators regularities are similar. Based on the correlation analysis, the factor analysis and the new constructed variable results, it can be found that the quality changes of the small watermelon fruit Jingxiu mainly manifest as the content changes of soluble solids, titratable acidity, flesh moisture and chlorophyll from 20 to 39 days after pollination process. Among these changes, the chlorophyll content changes notably in the course of 22 to 25 days after pollination process, while the other three primarily change in the course of 28 to 30 days. The quality becomes stable during the growth process of 31 to 39 days except some small fluctuations within a small range. The results can provide a basis for selection of parameters for optical non-destructive testing of small watermelon quality and maturity.