Abstract: Objective: This study aimed to investigate the changes in pulp quality characteristics of prune plum fruits during storage and to establish quality standards for selecting suitable raw materials for pulping. Methods: Plums were stored at 4 ℃ for seven weeks and the dynamic variations in fruit quality indices and the physicochemical properties of the resulting pulp were monitored throughout the storage period. Results: Fruit firmness decreased markedly during storage, with peel and flesh firmness declining by 65.3% and 87.3%, respectively. Soluble solids content (SSC), reducing sugars, and the solid-acid ratio increased in both fruit and pulp, whereas titratable acidity (TA) decreased. The contents of extractable polyphenols and anthocyanins in the fruit increased by 40.08% and 83.73%, respectively. With prolonged storage, pulp turbidity increased, apparent viscosity decreased, and particle size distribution became concentrated within 300~350 μm. Correlation analysis revealed that the pulp's a^* value was positively correlated with extractable polyphenols and anthocyanins in the fruit, while L^* and b^* values showed negative correlations. Moreover, pulp turbidity, suspension stability, and viscosity were significantly correlated with peel firmness (P<0.05). Conclusion: Principal component analysis identified the solid-acid ratio, consistency coefficient, and b^* value of the pulp as the core quality indicators, reflecting its sweet-sour balance, rheological behavior, and color characteristics, respectively. Based on these core indicators, a multivariate linear regression model was established to predict overall pulp quality. By measuring the fruit's solid-acid ratio, total sugar, and peel b^* value, this model enabled accurate prediction of pulp quality, providing a quantitative basis for determining the optimal harvest time and selecting suitable raw materials. Furthermore, the comprehensive quality score indicated that prune plums stored for 42 days exhibited the highest pulp quality, thereby defining the key parameters for optimal pulp production.