Embodiments of the present invention disclose a user pairing method, a device and a system for realizing user scheduling. The method comprises: determining a first user of a time-frequency resource according to a preset resource allocation criterion; searching a preset pairing table according to a downlink channel state quantization code of the first user; and obtaining a paired downlink channel state quantization code which is paired with the downlink channel state quantization code of the first user, wherein the preset pairing table includes a pairing relationship among the downlink channel state quantization codes obtained by pre-calculating; identifying a paired user of the first user from users to be paired, wherein a downlink channel state quantization code of the paired user is the same as the paired downlink channel state quantization code. Through adopting of the present invention, complexity of real-time calculation of pairing during user scheduling can be lowered.