A method for uplink multiuser data transmission and a system for uplink multiuser multiple input multiple output are provided. The method implemented by an access point (AP) includes: sending, indication information to at least two stations (STAs), wherein the indication information indicates that the at least two STAs perform an uplink multiuser data transmission; receiving, uplink data sent by the at least two STAs through channels, respectively; and demodulating, the uplink data using receiving beams corresponding to pre-estimated channels, respectively. According to the embodiments of the present disclosure, the AP receives the uplink data from multiple STAs through different channels from the STAs to the AP respectively, and demodulates data using the receiving beams corresponding to the channels respectively, thereby realizing that the AP performs separation and demodulation of the uplink data sent by multiple STAs and realizing the uplink multiuser data transmission.