Network delay detection method, device and system

The embodiments of the present invention disclose a network delay detection method, a device and a system. The method comprises the steps of sending an operation administration and maintenance (OAM) detection message to a transponder in a forwarding network by a controller; recording the first moment T1 of sending the OAM detection message; receiving a response message returned from the transponder by the controller; recording the fourth moment T4 of the response message reaching the controller, wherein the load of the response message contains the second moment T2 of the OAM detection message reaching the transponder and the third moment T3 of the response message reaching the transponder; and calculating the network delay according to any two moments out of the first moment T1, the second moment T2, the third moment T3 and the fourth moment T4 by the controller. In this way, the controller receives the response massage only once, so that the resource of control channels is saved.