The differences in fruit quality of ‘Cocktail’ grapefruit between the mode of facility cultivation and open cultivation （CK） were studied to improve the quality of ‘Cocktail’ grapefruit in Hubei Province. The results showed that the single fruit weight， transverse and longitudinal diameter and fruit shape index of facility cultivation were larger than those of CK. There was no significant difference in peel hardness during fruit development. There was a significant difference in peel hardness between facility cultivation and CK from 227 days after anthesis. Facility cultivation significantly increased the content of soluble solid in fruits to 10.43%. The content of titratable acid and Vc in facility cultivation was higher than that in CK. The results of GC-MS analysis showed that facility cultivation increased the content of sucrose in fruits to 49.63 mg/g. The results of real-time quantitative PCR analysis showed that facility cultivation increased the content of sucrose in fruits by upregulating the expression levels of CsSPS2， CsSUS2 and CsSUS4. It is indicated that facility cultivation can improve the fruit quality of ‘Cocktail’ grapefruit.