A method for adjusting power of a terminal includes monitoring, by the terminal, usage of an uplink carrier, where the carrier usage includes at least one of a quantity of carriers, duration of continuous use of one or more carriers, and a temperature of the terminal. The method further includes adding, by the terminal, a power back-off value during calculation of power headroom when the terminal detects that the carrier usage satisfies a preset condition, to reduce a value of power headroom of the one or more carriers. The method further includes reporting, by the terminal, the value of the power headroom to a network device.