Banana is a tropical fruit rich in nutrients and has important economic value. It is also one of the four major fruits in South China. Banana is a typical climacteric fruit. The release of ethylene in banana after harvest could accelerate the ripening and senescence of banana during postharvest storage, which would affect the storage freshness and economic value of banana. Therefore, it is necessary to explore the technology of improving banana postharvest storage quality, thus providing theoretical basis for practical application. In this study, postharvest bananas were treated by UV-C irradiation, citric acid immersion and the combination treatment, respectively. The bananas were stored in the dark for 12 days at a temperature of (20±2)℃ and a humidity of 60%-70%, and randomly sampled on the 1st, 6th, 9th and 12th day for each treatment during the storage period. The effects of the three methods on postharvest banana storage quality were studied by measuring physiological and quality indexes, such as hardness, weight loss rate, titratable acid content, and soluble solid content. The results indicated that the treatment with UV-C irradiation at the dose of 3.96×10^–2KJ/m² and combined treatment (3.96×10^–2KJ/m² UV-C irradiation together with 2.0% citric acid soak) resulted in better freshness effects than that of citric acid treatment, showing that the decrease of fruit hardness was significantly inhibited, the increase of weight loss rate was delayed, the increase of soluble solid content and the decrease of titratable acidity content were inhibited, and the sugar-acid ratio were maintained. At the end of storage, UV-C irradiation and combined treatment increased the hardness of bananas by 9.09% and 13.63%, reduced weight loss by 22.00% and 11.43%, and decreased sugar-acid ratio by 40.00% and 42.30%, respectively, compared with the control group. In addition, UV-C irradiation and combined treatment effectively inhibited the decrease of flavonoids, phenols and vitamin C contents, and improved the DPPH free radical scavenging rate and antioxidant capacity. At the end of storage, UV-C irradiation and combined treatment increased the vitamin C contents of bananas by 0.82% and 1.27%, the total polyphenol contents by 25.92% and 41.65%, the total flavonoids contents by about 30.00%, and DPPH radical scavenging rate by 13.98% and 36.59%, respectively, compared with the control group. In conclusion, both UV-C irradiation and combined treatment can improve storage quality and prolong shelf life of postharvest bananas. Therefore, these two methods can be used as green, safe and effective post-harvest preservation technologies for bananas.