Building hub is the key to establish international competitive route network and also the core of improving the transfer ability of the three biggest airports in China.This paper focuses on two evaluating indicators, connecting rate and connecting efficiency.At first, based on the deduction and establishment of the model of transfer opportunity, theoretical value of transfer opportunity is calculated and the flight connection module diagram is draw out.Then, the main influence factors are analysed and the model is modified, considering the real situation of airport operation.Finally, optimization measure is presented in order to improve the transfer service by the leading of airport management organization, according to the theory of Business Process Re-engineering.