The invention relates to a physical layer network coding-based joint antenna selection space multiplexing method, and belongs to the technical field of wireless communication. The method comprises the following steps that: a relay selects an antenna set which participates in communication; two users which perform bidirectional communication transmit pre-coded information to the relay at the same time; the relay performs physical layer network coding maximum likelihood detection on superimposed signals from different users to directly obtain network coding symbols; the relay broadcasts the network coding symbols back to the users; and the users decode the pre-coded information and extract the information of the other user by utilizing self-information. By the method, the frequency spectrumutilization efficiency and the energy utilization efficiency of a bidirectional delay network are improved effectively, multi-stream high-speed transmission is realized, and relay decoding complexityis reduced.