The invention discloses a layered multi-domain-based routing determining method. The method comprises the steps of acquiring source node information and sink node information in a service request; determining a type of the service request according to the source node information and the sink node information; and determining an optimal routing path according to the type of the service request. According to the method, the routing path is selected through coordinated routing of multiple controllers, so that the resource use ratio is increased effectively, the cost of the controller is lowered, and the path with minimum cost is selected as the optimal path.