A method performed by a terminal connecting with a first base station of a first radio access technology and a second base station of a second radio access technology different from the first radio access technology based on a dual connectivity in a wireless communication system, the method comprising: receiving, from the first base station, a downlink signal associated with a transmission of a first uplink signal; identifying that a resource for the first uplink signal to be transmitted to the first base station overlaps with a resource for a second uplink signal to be transmitted to the second base station, based on the downlink signal; identifying whether a sum of first transmission power for the first uplink signal and second transmission power for the second uplink signal exceeds a maximum transmission power of the terminal; identifying whether a processing time associated with the downlink signal is expired before a start symbol of a subframe for the second uplink signal, in case that the sum exceeds the maximum transmission power of the terminal; and performing a transmission for the first uplink signal using the first transmission power and a transmission for the second uplink signal based on a result of the identification, wherein the transmission for the second uplink signal is performed using a third transmission power, in case that the processing time is expired before the start symbol, the third transmission power being lower than the second transmission power, and wherein the transmission for the second uplink signal is performed using the second transmission power and stopped at a timing of a start point of the transmission for the first uplink signal, in case that the processing time is expired after the start symbol. receiving, from the first base station, a downlink signal associated with a transmission of a first uplink signal; identifying that a resource for the first uplink signal to be transmitted to the first base station overlaps with a resource for a second uplink signal to be transmitted to the second base station, based on the downlink signal; identifying whether a sum of first transmission power for the first uplink signal and second transmission power for the second uplink signal exceeds a maximum transmission power of the terminal; identifying whether a processing time associated with the downlink signal is expired before a start symbol of a subframe for the second uplink signal, in case that the sum exceeds the maximum transmission power of the terminal; and performing a transmission for the first uplink signal using the first transmission power and a transmission for the second uplink signal based on a result of the identification, wherein the transmission for the second uplink signal is performed using a third transmission power, in case that the processing time is expired before the start symbol, the third transmission power being lower than the second transmission power, and wherein the transmission for the second uplink signal is performed using the second transmission power and stopped at a timing of a start point of the transmission for the first uplink signal, in case that the processing time is expired after the start symbol.