A method for detecting rogue behaviour, comprising: for the upstream optical signal of each Passive Optical Network port, constructing and transmitting via an optical transceiver a short timeslot, by an Optical Line Terminal; controlling, by the OLT, the optical transceiver to conduct a first Signal Detect on the upstream optical signal according to the short timeslot to obtain a first detection result, wherein the first SD comprises a sampling detection; judging, by the OLT, whether the upstream optical signal is valid according to the first detection result; in a case that the upstream optical signal is valid, constructing and transmitting via the optical transceiver a long timeslot, by the OLT, and, controlling, by the OLT, the optical transceiver to conduct a second SD on the upstream optical signal according to the long timeslot to obtain a second detection result, wherein the second SD comprises the sampling detection, a length of the short timeslot is shorter than a length of the long timeslot; and determining, by the OLT, whether the current PON port is experiencing rogue behavior according to the second detection result; wherein determining, by the OLT, whether the current PON port is experiencing rogue behaviour according to the second detection result comprises: judging, by the OLT, whether the upstream optical signal is valid according to the second detection result; in a case that the upstream optical signal is valid, determining, by the OLT, that the current PON port is experiencing rogue behavior; in a case that the upstream optical signal is not valid, determining, by the OLT, that the current PON port is experiencing upstream drift of window. for the upstream optical signal of each Passive Optical Network port, constructing and transmitting via an optical transceiver a short timeslot, by an Optical Line Terminal; controlling, by the OLT, the optical transceiver to conduct a first Signal Detect on the upstream optical signal according to the short timeslot to obtain a first detection result, wherein the first SD comprises a sampling detection; judging, by the OLT, whether the upstream optical signal is valid according to the first detection result; in a case that the upstream optical signal is valid, constructing and transmitting via the optical transceiver a long timeslot, by the OLT, and, controlling, by the OLT, the optical transceiver to conduct a second SD on the upstream optical signal according to the long timeslot to obtain a second detection result, wherein the second SD comprises the sampling detection, a length of the short timeslot is shorter than a length of the long timeslot; and determining, by the OLT, whether the current PON port is experiencing rogue behavior according to the second detection result; wherein determining, by the OLT, whether the current PON port is experiencing rogue behaviour according to the second detection result comprises: judging, by the OLT, whether the upstream optical signal is valid according to the second detection result; in a case that the upstream optical signal is valid, determining, by the OLT, that the current PON port is experiencing rogue behavior; in a case that the upstream optical signal is not valid, determining, by the OLT, that the current PON port is experiencing upstream drift of window. judging, by the OLT, whether the upstream optical signal is valid according to the second detection result; in a case that the upstream optical signal is valid, determining, by the OLT, that the current PON port is experiencing rogue behavior; in a case that the upstream optical signal is not valid, determining, by the OLT, that the current PON port is experiencing upstream drift of window.