The invention discloses a power allocation method, which comprises the steps of configuring guaranteed power represented by the percentage of the maximum available power for a master eNodeB (MeNB) and a slave eNodeB (SeNB), and allocating power for a master cell group (MCG) and a secondary cell group (SCG) respectively according to the guaranteed power; when uplink control information (UCI) of the MCG and UCI of the SCG are identical in type, configuring the cell priority of the SCG to be not lower than the cell priority of the MCG; allocating the residual power for the MCG and the SCG based on cell priorities, wherein the residual power is the power left after allocation is performed according to the guaranteed power. The invention further discloses a power allocation device, which can perform power allocation by combining channel occupation conditions on an unlicensed carrier, and enables power allocation in an LAA system to adapt to changes in channel occupation condition on the unlicensed carrier, thereby effectively utilizing available power resources, and ensuring the system performance.