Disclosed are a method and device for transmitting uplink control information (UCI). By applying technical solutions of embodiments of the present invention, implemented is a method for simultaneously transmitting an ACK/NACK and cycle CSI on a channel resource corresponding to a current subframe: dynamically determining, on the basis of a threshold number of bits simultaneously transmitted with the UCI in the current subframe, also of the maximum number of feedback bits and of the minimum number of feedback bits of the ACK/NACK in the current subframe, ACK/NACK bits and CSI bits simultaneously transmitted in the current frame, thus ensuring that the sum of the bits simultaneously transmitted does not exceed the threshold number of bits simultaneously transmitted with the UCI in the current subframe, preventing as much as possible ACK/NACK merging and CSI discarding, and protecting to the maximum extent the accuracy and completeness of UCI transmission.