A method includes separately collecting, by a terminal, a transmit power of the terminal at different time points in a second duration after a first duration from a power-on moment to obtain a plurality of transmit powers, calculating an average transmit power of the transmit powers, determining based on the average transmit power, a specific absorption rate (SAR) corresponding to the average transmit power, and decreasing a transmit power of the terminal after the second duration when the terminal determines that the SAR is greater than a preset threshold.