Provided is a method for forwarding service data, a network device, and a network system. The forwarding method may include the following operation. A forwarding path for service data is determined according to network resource configuration information of a designated network and a network slice of the service data, wherein the network resource configuration information indicates one or more network slices associated with one or more network resources of the designated network, and a network slice associated with a network resource of the determined forwarding path matches the network slice of the service data; and the service data is forwarded according to the forwarding path.