Abstract: To examine how different harvesting periods affect the storage quality of 'Satsuma' plum fruits, this study analyzed 13 quality and physiological metrics post-harvest and utilized principal component analysis (PCA) and mathematical models to assess (0±0.5)℃ low temperature storage quality across three different harvesting periods (100 d after flowering, 103 d after flowering, 106 d after flowering). The results showed that harvesting at 103 days after full bloom led to the best preservation effect. Additionally, the hardness and total acidity of plum fruit decreased by 37.37% and 27.06% respectively until the end of the storage period, which was the slowest. Furthermore, changes in relative conductivity, anthocyanins, total soluble solids, malondialdehyde, total phenols, and flavonoids were relatively smooth. The activity of polyphenol oxidase was low, while peroxidase, superoxide dismutase, and catalase activities were high, specifically catalase activities. After conducting PCA analysis, it was determined that PC1, PC2, and PC3 accurately capture 87.472% of the relevant information. These results suggested that varying harvesting periods would have significant impacts on all indicators. The mathematical model analysis revealed that the plum fruits harvested at 100, 103, and 106 days after bloom, and stored for 56 days, had comprehensive scores of 1.06, 0.99, and 2.69, respectively. Lower comprehensive scores indicated better quality, so the order of preservation effect was as follows: 103 days after bloom>100 days after bloom>106 days after bloom. The study provides a theoretical framework for evaluating postharvest preservation and quality of plum fruits, along with technical parameters to enable timely harvesting.