A method for adjusting power of a terminal, wherein the method comprises: monitoring, by the terminal, usage of an uplink carrier, wherein the carrier usage comprises at least one of a quantity of carriers, duration of continuous use of one or more carriers, or a temperature of the terminal (step 201); 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; and reporting, by the terminal, a value of the power headroom to a network device (step 202); wherein the monitoring, by the terminal, usage of the uplink carrier comprises: monitoring, by the terminal, the temperature of the terminal; and the adding, by the terminal, the power back-off value during calculation of power headroom when the terminal detects that the carrier usage satisfies the preset condition comprises: adding, by the terminal, the power back-off value during the calculation of the power headroom when the temperature of the terminal reaches a first temperature threshold; after the adding, by the terminal, the power back-off value during the calculation of the power headroom when the temperature of the terminal reaches the first temperature threshold, the method further comprises: stopping adding, by the terminal, the power back-off value during the calculation of the power headroom when the temperature of the terminal drops to a second temperature threshold, wherein the first temperature threshold is greater than the second temperature threshold. monitoring, by the terminal, usage of an uplink carrier, wherein the carrier usage comprises at least one of a quantity of carriers, duration of continuous use of one or more carriers, or a temperature of the terminal (step 201); 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; and reporting, by the terminal, a value of the power headroom to a network device (step 202); wherein the monitoring, by the terminal, usage of the uplink carrier comprises: monitoring, by the terminal, the temperature of the terminal; and the adding, by the terminal, the power back-off value during calculation of power headroom when the terminal detects that the carrier usage satisfies the preset condition comprises: adding, by the terminal, the power back-off value during the calculation of the power headroom when the temperature of the terminal reaches a first temperature threshold; after the adding, by the terminal, the power back-off value during the calculation of the power headroom when the temperature of the terminal reaches the first temperature threshold, the method further comprises: stopping adding, by the terminal, the power back-off value during the calculation of the power headroom when the temperature of the terminal drops to a second temperature threshold, wherein the first temperature threshold is greater than the second temperature threshold. monitoring, by the terminal, the temperature of the terminal; and the adding, by the terminal, the power back-off value during calculation of power headroom when the terminal detects that the carrier usage satisfies the preset condition comprises: adding, by the terminal, the power back-off value during the calculation of the power headroom when the temperature of the terminal reaches a first temperature threshold; after the adding, by the terminal, the power back-off value during the calculation of the power headroom when the temperature of the terminal reaches the first temperature threshold, the method further comprises: stopping adding, by the terminal, the power back-off value during the calculation of the power headroom when the temperature of the terminal drops to a second temperature threshold, wherein the first temperature threshold is greater than the second temperature threshold.