During　TBM　tunnelling,　the　rock　breaking　by　cutters　usually　induces　vibration.　The　cutterhead　vibration　is　composed　of　all　cutter　vibrations.　On　the　one　hand,　cutterhead　vibration　directly　affects　the　life　of　the　cutter,　cutterhead　and　main　gear.　On　the　other　hand,　cutterhead　vibration　reflects　the　TBM　excavation　performance.　In　this　paper,　a　cutterhead　vibration　monitoring　system　for　TBM　tunnelling　was　developed.　The　system　consisted　of　the　data　acquisition　module,　communication　and　control　module,　as　well　as　data　processing　and　display　module.　Acceleration　sensor,　gyroscope　and　clock　chip　were　integrated　into　a　sensor　board　to　acquire　triaxial　vibration　data,　cutterhead　rotating　status　and　acquisition　time.　The　installation　structure　with　anti-hit　and　water-proof　functions　was　designed　to　ensure　the　stable　operation　of　the　system.　Three　types　of　data　acquisition　modes　were　proposed　to　meet　the　different　monitoring　scenarios.　The　system　was　applied　in　a　TBM　tunnelling　project.　Based　on　the　normal　monitored　data　in　TBM　tunnelling　and　penetration　tests　data,　the　differences　in　amplitude　and　frequency　of　triaxial　vibration,　as　well　as　the　effect　of　geological　conditions　and　operating　parameters　on　cutterhead　vibration　characteristics　were　analyzed.　The　engineering　application　showed　that　this　system　can　reflect　the　changes　of　the　geological　conditions　and　operating　parameters,　providing　guidance　for　the　TBM　tunnelling.