The invention provides a fault diagnosis information transferring and processing method for a normalization management interface of a device. The method is applied to a network management system which consists of a network management station (NMS), and main and sub agencies operating on an optical line terminal (OLT) device. The method is characterized by comprising the following steps: detecting the type of a fault generated by the OLT device by the sub agency, and sending a message containing the type of the fault to the main agency; judging the urgency extent of the fault by the main agency, and packaging the fault message into a packet to be sent to the NMS; analyzing the packet by the NMS and processing the fault in a classified way; receiving a responding packet returned by the NMS by the main agency. By the adoption of the method, the defect that the fault management of the OLT device is not reliable is overcome, the transferring effectiveness of the message between the main and the sub agencies is improved, the cost for improving the reliable transferring of the fault notification for a network system is saved, the main agency in the OLT can be ensured to send a fault diagnosis notification to an expected destination without omissions, so that the device can be maintained and managed in time.