The present disclosure provides an uplink carrier aggregation device and a mobile terminal. The uplink carrier aggregation device comprises: a radio frequency transceiver, at least two power amplifiers, a power amplifier power module, a control chip, a multiplexer and an antenna switch. The radio frequency transceiver is connected to the at least two power amplifiers. The at least two power amplifiers are connected to the multiplexer. The multiplexer is connected to the antenna switch. The control chip is connected to the radio frequency transceiver and the power amplifier power module, to determine a power voltage each power amplifier needs, determine, according to the maximum value of the power voltage, a target voltage that the power amplifier power module needs to output, and send a power supply instruction to the power amplifier power module. The power amplifier power module is connected to the at least two power amplifiers, and is configured to adjust the target voltage according to the power supply instruction and output the target voltage to the at least two power amplifiers.