A method and user equipment for performing an uplink transmission in a wireless communication system, are discussed. The method includes allocating transmission power to a first uplink transmission and a second uplink transmission when a total power in a transmission period including at least one or more OFDM symbols exceeds maximum power, wherein each of the first and second uplink transmissions is one of physical uplink shared channel (PUSCH) transmission, physical uplink control channel (PUCCH) transmission, physical random access channel (PRACH) transmission and sounding reference signal (SRS) transmission; and performing the first and second uplink transmissions according to the allocated transmission power, wherein the allocation of the transmission power is performed according to priority information.