The invention relates to the technical field of cloud computing, and in particular relates to a multi-level software-defined data centre architecture and a method thereof. A terminal user logs in a multi-level portal platform to customize cloud resources, determines an order form to buy the cloud resources, and uses the cloud resources; the multi-level portal platform calls a multi-level agent platform in a timed manner to perform order form conversion, and obtains and displays various terminal user resources; and the multi-level agent platform calls a data centre cloud platform interface, creates the cloud resources on a cloud platform, and returns resource information to the portal platform. By means of the multi-level software-defined data centre architecture and the method thereof disclosed by the invention, unified management and sale of data centre resources can be realized; and the multi-level software-defined data centre architecture and the method thereof are particularly suitable for resource management of a public cloud platform.