The optical fiber pre-waing system (OFPS) has been gradually considered as one of the important means for pipeline safety monitoring.Intrusion signal types are correctly identified which could reduce the cost of troubleshooting and maintenance of the pipeline.Most of the previous feature extraction methods in OFPS are usually quested from the view of time domain.However,in some cases,there is no distinguishing feature in the time domain.In the paper,firstly,the intrusion signal features of the running,digging,and pick mattock are extracted in the frequency domain by multi-level wavelet decomposition,that is,the intrusion signals are decomposed into five bands.Secondly,the average energy ratio of different frequency bands is obtained,which is considered as the feature of each intrusion type.Finally,the feature samples are sent into the random vector functional-link (RVFL) network for training to complete the classification and identification of the signals.Experimental results show that the algorithm can correctly distinguish the different intrusion signals and achieve higher recognition rate.