The embodiments of the present disclosure disclose a method for uplink multiuser data transmission and a system for uplink multiuser multiple input multiple output. The method includes: sending, by an access point AP, indication information to at least two stations STAs, wherein the indication information is used for indicating that the at least two STAs perform an uplink multiuser data transmission; receiving, by the AP, uplink data sent by the at least two STAs through channels from the at least two STAs to the AP, respectively; and demodulating, by the AP, the uplink data sent by the at least two STAs using receiving beams corresponding to pre-estimated channels from the at least two STAs to the AP, 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 perform separation and demodulation of the uplink data sent by multiple STAs and realizing the uplink multiuser data transmission.