A method and an apparatus for transmitting uplink control information (UCI), performed by a user equipment, in a wireless communication system are provided. The method comprising: generating encoded information bits by performing channel coding on information bits of the UCI; generating a modulation symbol sequence by modulating the encoded information bits; generating a spread sequence by block-wise spreading on the modulation symbol sequences with an orthogonal sequence; and transmitting the spread sequence to a base station through an uplink control channel, wherein the information bits of the UCI comprises a first UCI bit sequence and a second UCI information bit.