A hierarchical beamforming method is provided, which comprises the following steps. Firstly, the vectors of the transmitter and the receiver are hierarchically indexed by using the codebooks with different coding methodology to generate hierarchical coding structures. Then, the corresponding vector fields between the transmitter and the receiver are switched according to the hierarchical coding structures. Thereafter, at least two aligning vector fields with greatest gain are detected. Finally, the corresponding aligning index pairs are used to build the channels.