Abstract. This study was conducted to investigate the optimum storage temperature and the effect of 1-methylcyclopropene (1-MCP) on the postharvest physiology and quality of plumcot (Prunus salicina Lindle. × Prunus armeniaca L.) 'Harmony' fruits. plumcot fruits were stored at 0, 5, 10, and 20°C, respectively, with three different ripeness stages grouped by skin color development. Furthermore, we treated 1 μL･L -1 1-MCP was treated at 10°C for 17 hours and stored at 10°C for 12 days to evaluate the effectiveness for better shelf-life. The results indicated that lower storage temperature than room temperature effectively reduced the respiration rate with delaying quality changes. While, the fruits showed worse fruit taste than the fruits stored at 10 and 20°C. Reversely, the fruits stored at 20°C showed more respiration rate and ethylene production. 1-MCP treatment effectively reduced the skin red color development, ethylene production, CO 2 and softening of plumcot 'Harmony' fruits. Overall data indicated that the optimum harvest time and storage temperature could be 30-50% red color and near 10°C. Postharvest 1-MCP application at the level of 1.0 μL･L -1 could maintain fruit quality well in plumcot fruits.