A signal transmission method, a related device, and a system are provided. The method includes a terminal receiving configuration information, where the configuration information indicates N sets of power control parameters configured for M uplink resources or uplink resource sets, where M≥1, M is a positive integer, N>1, and N is a positive integer; and the terminal transmits an uplink signal on the M uplink resources or uplink resource sets, where transmission power for transmitting the uplink signal on the M uplink resources or uplink resource sets is determined based on a first power control parameter, and the first power control parameter is selected from the N sets of power control parameters. According to the foregoing solution, uplink transmission power can be more flexibly adjusted, and power efficiency in uplink transmission and uplink transmission performance can be maximized.