A service orchestration method and apparatus in SDN, and a storage medium are described. The method includes: determining whether a current SDN open network platform resource meets an SDN open network platform resource requested by an SDN application after receiving a request of using the SDN open network platform resource sent from the SDN application via an external application interface, determining whether an application engine function module and an application extension function module meet an execution of the SDN application when the requested resource is met, and loading an application engine function of the application engine function module or an application extension function of the application extension function module when meeting; and applying for the resource required by the SDN application from a controller layer of the SDN, and allocating the applied resource to the loaded application engine function or application extension function.