The invention discloses a channelized receiving method based on a spectrum interleaved light local oscillator. According to the invention, the spectrum interleaved light local oscillator consisting ofa group of N light local oscillators of which frequency intervals sequentially are kfFSR+BCH, kfFSR+3BCH, kfFSR+BCH, kfFSR+3BCH...... is utilized to carry out expansion on channels, wherein k is equal to 0 or 1, BCH represents a channel bandwidth, and fFSR represents a preset frequency, so that sharing of two channels on one light local oscillator is implemented, and for N light local oscillators, channelization of 2N channels can be implemented, thereby reducing the number of the local oscillators by 50% and compared to a conventional scheme, at least doubling a spectrum utilization rate andchannelization efficiency; and the requirement for a low-frequency electric signal image-frequency rejection ratio is effectively reduced, and crosstalk between the channels is reduced.