The invention provides a magnetic resonance signal receiving device, a receiver coil channel selector and a magnetic resonance imaging system. The magnetic resonance signal receiving device comprisesa plurality of local coils and a receiver coil channel selector. The plurality of local coils are capable of respectively receiving magnetic resonance signals that are generated when magnetic resonance detection is carried out on a detected object; each local coil consists of a plurality of antenna units and a time division multiplexing module; and the time division multiplexing modules enable themagnetic resonance signals received by all antenna units respectively to be outputted only by one output line. The receiver coil channel selector has a plurality of input interfaces connected with respective output lines of the plurality of local coils correspondingly; a synthesizer is arranged in the receiver coil channel selector; and all or one part of magnetic resonance signals that are outputted by the output lines of all local coils are synthesized at time or power by the synthesizer to obtain one or more magnetic resonance synthesis signals.