The present disclosure relates to system information transmission methods and apparatus. One example method includes receiving, by a first network node, at least one type of system information (SI) from a second network node, where the at least one type of SI includes first SI, receiving, by the first network node, a request message from a terminal device, where the request message is used to request the first SI, and sending, by the first network node, the first SI to the terminal device based on the request message and the at least one type of SI.