Convergence　deformation　is　an　important　index　for　evaluating　structural　stability　and　safety　during　the　running　periods　of　shield　tunnels.　Because　of　some　technical　and　economic　difficulties,　the　traditional　observation　methods,　which　can　be　only　used　to　monitor　a　few　predetermined　and　uniformly　spaced　segment　rings,　can＇t　monitor　convergence　deformation　of　all　segment　rings　of　actual　shield　tunnels　which　usually　have　the　length　of　several　kilometers　or　even　longer.　In　this　study,　the　distributed　optical　fiber　strain　sensing　technique　is　proposed　to　cover　every　segment　rings　in　tunnels,　and　a　new　method　is　presented　to　monitor　the　convergence　deformation　of　arbitrary　rings　by　means　of　the　hoop　strain　measurements　along　the　rings.　In　the　proposed　method,　a　linear　and　explicit　function　relationship　between　the　convergence　deformation　and　the　strain　distribution　is　put　forward,　and　it　is　found　that　the　precision　of　the　monitored　deformation　mainly　depends　on　that　of　the　strain　measurements　from　the　arranged　distributed　fiber　optical　sensors.　Furthermore,　a　numerical　simulation　is　conducted　to　validate　the　proposed　method.　Additionally,　an　experiment　on　a　small-scale　concrete　segment　ring　model　is　carried　out　to　verify　the　practical　precision　of　the　proposed　method.　Experimental　results　show　that　the　maximum　monitoring　error　of　the　estimated　convergence　deformation　is　only　15%.