An embodiment of the invention provides an SDN-based tiered routing path determination method and device that are applied to an inter-domain controller and an intra-domain controller in a software-defined network; the SDN-based tiered routing path determination method comprises the following steps: a cross-domain request of a data flow sent by the intra-domain controller is obtained; according to the cross-domain request, a start point network domain and an intermediate network domain where a source node is positioned are determined; network performance information sent by the intra-domain controller is obtained; according to the network performance information and a plurality of preset cross-domain route selection strategies, an optimal routing path for transmitting the above data flow in all network domains is determined; according to the start point network domain and the intermediate network domain, boundary information of a first network domain and boundary information of a second network domain are determined and sent to the intra-domain controller, and the intra-domain controller is enabled to determine the optimal routing path for data transmission in the network domains. Via the SDN-based tiered routing path determination method and device, optimal design of a cross-domain routing path can be realized.