A data transmission method includes receiving a service request sent by a terminal device. The method also includes determining, based on the service request, a target transmission path of service data corresponding to the service request and a change policy corresponding to the target transmission path. The method further includes changing, according to the change policy, a current content delivery network (CDN) to a target CDN. The target CDN includes a plurality of serving nodes corresponding to the target transmission path. The method additionally includes sending an indication message to a first serving node in the target CDN to indicate the first serving node to send the service data to the terminal device through the target transmission path; or sending an indication message to a second serving node in the target CDN to indicate the second serving node to send the service data to the terminal device.