A power control method and device are used for achieving transmit power control of a User Equipment (UE) in a multi-carrier mode. The power control method includes: calculating a transmit power of a UE when the UE sends data through a plurality of carriers; and performing power compression on each carrier either step by step according to property parameters of each carrier or synchronously according to a compression ratio, when the transmit power of the UE exceeds a preset maximum transmit power. A power control device is further provided.