Abstract: In this experiment, the effect of litchi trees factors, including the concentrations of GA3, ABA, ZR, IAA and carbonitride, on flower bud differentiation(FBD) during two litchi cultivars(Litchi chinensis Sonn. cv. Feizixiao and Litchi chinensis Sonn. cv. Edanli) FBD was studied. The results showed that significant differences were existed in the concentrations of endogenous phytohormones and carbonitride of two litchi cultivars: three positions(high parts, middle parts and lower parts of canopies) and two directions(northeast and southwest). The most significant differences were existed in the FBD of two different litchi cultivars. The FBD results obtained in Feizixiao were better than those of Edanli. According to the analyses of partial least twice multiplied regression between the trees factors and the items of litchi FBD, the trees factors were found to affect the litchi FBD, especially the number of inflorescence low part divaricating, the length of inflorescence, the diameter of inflorescence low part and the number of side spikes. Response models of litchi FBD to the tree factors were gained in the paper.