This application discloses a downlink transmit power control method and apparatus. The downlink transmit power control method in embodiments of this application includes: receiving, by a child node, a downlink transmission carrying a measurement signal and sent by a parent node on a reference resource; determining, by the child node, a power adjustment value of downlink transmit power of the parent node based on a measurement result of the measurement signal; and sending, by the child node, a power adjustment command to the parent node, where the power adjustment command is used to indicate the power adjustment value.