This application provides example methods for establishing a service path in a transport network and example systems. One example method includes, obtaining, by an automatically switched optical network (ASON) first node, a service path computation result path. The service path includes the ASON first node, an ASON last node, and at least one first edge network node. The method also includes sending, by the ASON first node, a path establishment request message to a downstream node. The path establishment request message carries cross-connection configuration information of the ASON last node and the at least one first edge network node. The method further includes receiving, by the ASON first node, a path establishment response message of the downstream node. The path establishment response message indicates that cross-connection configuration for the ASON last node and the at least one first edge network node is complete.