The present invention provides a method for controlling transmission power of an uplink control channel carried out by an user equipment in a wireless communication system and an user equipment using the method. The method comprises: receiving uplink power control information; and determining transmission power of an uplink control channel based on the uplink power control information, wherein the uplink power control information includes a power offset value determined according to whether transmit diversity is applied when the uplink control channel is transmitted through a channel selection scheme.