A method, device, and system for communication signal transmission are provided, which relate to the field of communications, so as to improve reception performance of the network. The method includes dividing, by a multi-frequency receiver, Radio Frequency (RF) signals by frequency bands received from an antenna to obtain RF signals of different frequency bands; sending a first group of RF signals of a predetermined frequency band to an RF unit so that the RF unit converts the received first group of the RF signals of the predetermined frequency band into first baseband digital signals and sends the first baseband digital signals to a baseband processing unit; and converting a second group of the RF signals of the predetermined frequency band into second baseband digital signals and sending the second baseband digital signals to the baseband processing unit by using a digital baseband interface