This application provides a signal transmission method and apparatus to reduce system overhead. The method is applied to a terminal device, and the method includes: receiving first configuration information from a network device, where the first configuration information indicates S reference signal resources, the S reference signal resources include K reference signal ports, the K reference signal ports are K reference signal ports in M reference signal ports, each of the M reference signal ports corresponds to a distinct antenna port of the terminal device, and S, K, and M are positive integers; and sending the S reference signal resources to the network device based on the first configuration information through the K reference signal ports.