A network as a service, NaaS, service cross-domain orchestration method, implemented by an orchestration device, comprising: obtaining first information about a first user-to-network interface, UNI, and second information about a second UNI in a multi-domain network according to an NaaS service request received by the orchestration device which is used to request the orchestration device to establish an NaaS service between a first terminal and a second terminal, wherein the first UNI is used by the first terminal to access a first network domain, the second UNI is used by the second terminal to access a second network domain, and the multi-domain network comprises at least two network domains; obtaining a cross-domain path between the first UNI and the second UNI; and separately sending, a first connection requirement and a second connection requirement of each network domain of network domains that the cross-domain path passes through, to a control device in each corresponding network domain so that the control device in each network domain establishes an intra-domain data connection in the network domain and an inter-domain data connection between the network domain and an adjacent domain on the cross-domain path according to the first connection requirement and the second connection requirement, wherein the first connection requirement is an intra-domain connection requirement of each network domain, and the second connection requirement is an inter-domain connection requirement between each network domain and an adjacent domain on the cross-domain path and the first connection requirement and the second connection requirement of each network domain are used for establishing, by the control device in each network domain, the NaaS service from the first terminal to the second terminal. obtaining first information about a first user-to-network interface, UNI, and second information about a second UNI in a multi-domain network according to an NaaS service request received by the orchestration device which is used to request the orchestration device to establish an NaaS service between a first terminal and a second terminal, wherein the first UNI is used by the first terminal to access a first network domain, the second UNI is used by the second terminal to access a second network domain, and the multi-domain network comprises at least two network domains; obtaining a cross-domain path between the first UNI and the second UNI; and separately sending, a first connection requirement and a second connection requirement of each network domain of network domains that the cross-domain path passes through, to a control device in each corresponding network domain so that the control device in each network domain establishes an intra-domain data connection in the network domain and an inter-domain data connection between the network domain and an adjacent domain on the cross-domain path according to the first connection requirement and the second connection requirement, wherein the first connection requirement is an intra-domain connection requirement of each network domain, and the second connection requirement is an inter-domain connection requirement between each network domain and an adjacent domain on the cross-domain path and the first connection requirement and the second connection requirement of each network domain are used for establishing, by the control device in each network domain, the NaaS service from the first terminal to the second terminal.