Device and method of handling uplink power control

A communication device of handling uplink (UL) power control, comprising:

• a storage unit;
• and
• a processing means, coupled to the storage unit, wherein the storage unit stores instructions, and the processing means is configured to execute the instructions of:
• determining that a first UL transmission on a first serving cell of a network and a second UL transmission on a second serving cell of the network are overlapped;
• keeping a transmission power level of the first UL transmission and adjusting a first transmission power level of the second UL transmission to a second transmission power level of the second UL transmission, according to a power level limit of the communication device, if a sum of the transmission power level of the first UL transmission and the first transmission power level of the second UL transmission is greater than the power level limit;
• performing the first UL transmission according to the transmission power level of the first UL transmission;
• and
• performing the second UL transmission according to the second transmission power level of the second UL transmission.