The present invention discloses a control information transmission method, a user equipment, and a base station. The method includes: obtaining a data channel transmission mode configured by a base station; determining a downlink control information DCI format set corresponding to the transmission mode, where the DCI format set includes a first DCI format, and the first DCI format includes single-codeword control information; and detecting, according to the DCI format set, control signaling sent by the base station and corresponding to the DCI format set. The user equipment includes a first obtaining module, a first determining module, and a detecting module. The base station includes a configuring module, a first determining module, and a first sending module.