Objective: This study aimed to provide theoretical basis for hardy kiwifruit quality improvement and rational utilization. Methods: Taking the main variety 'Longcheng No. 2' and line 'Haijia' as experimental materials, the changes of basic quality indexes, contents of total phenolics and flavonoids were analyzed during fruit development. On this basis, the antioxidant capacities were comprehensively evaluated by three assays (FRAP iron reducing ability, ABTS radical scavenging ability and DPPH radical scavenging ability). Furthermore, the differences of total phenolics and antioxidant capacities in different parts of fruit were compared. Results: ① The contents of soluble solids, titratable acids and Vc in the fruits of the two varieties (lines) showed a trend of continuous increasing during fruit development. ② The chlorophyll contents of two varieties (lines) both declined constantly at the early stage of fruit development, and then increased continuously from 64 days after blooming. The carotenoids of two varieties (lines) also increased continuously from 64 days after blooming, meanwhile, the anthocyanins of 'Haijia' increased gradually. ③ The contents of total phenolics, flavonoids and three antioxidant capacities all decreased significantly during fruits ripening. The correlation analysis showed that among all quality indexes, total phenolics and flavonoids had extremely significant positive correlations with the three antioxidant capacities. ④ In mature fruits, the contents of total phenolics and flavonoids in the peel were significantly higher than those in the flesh, which indicated strong antioxidant capacities. Conclusion: The antioxidant capacities of two varieties (lines) of hardy kiwifruit decreased significantly during fruit development. Moreover, the content of total phenolics, especially flavonoids are the main components to affect antioxidant capacities during fruit development. In the different fruit parts, the peel has higher antioxidant capacities, but it is also the main source of astringency.