The invention provides a path detection method and a control device. The method comprises the steps that the control device detects a first physical path, thereby determining path state information of the first physical path, wherein the first physical path is an overlapped physical path among M physical paths, and the M is a positive integer greater than or equal to 1; and the control device determines path states of N virtual paths borne by the M physical paths according to the path state information of the first physical path, wherein the N is greater than or equal to 2. The consumption and waste of resources used in a detection process can be reduced.