Abstract: Changes of endogenous gibberellins (GA4 + 7 ), cytokinin (ZRs), auxin(IAA) levels and fruit growth pattern were studied during fruit development of longan (Dimocarpus longan Lour. cv. Chuliang), and the relationships between endogenous hormones and fruit development were discussed. The results showed that the ZRs contents in skin and seed were high in the early stage of fruit development and low in the late stage; the IAA content was very low before 29 days after full bloom(DAFB) and rose to a high level after 44 DAFB; the peaks of GA4+7 were found on 14,44 and 92 DAFB, while the low content occurred on 29 and 60 DAFB, respectively. According to the results, it seemed that the high ZRs level in the early stage was correlated with cell division; low IAA and GA4+7 content might be associated with the physiological drop of longan fruits; high level of IAA might promote fruit expansion.