Taken the section between Jinfeng Road Station and Fenhu Road Station of Suzhou subway line as research subject, this article made a 3D elastoplasticity numerical simulation of the construction of shield tunnel, applying numerical calculation and the non-linear finite element software to study the deformation of soil, the cracking of segments, the dislocation between segments, the changing of shearing strength of the bolts which connecting the segments and segment internal force changing, etc. The results show that the un-grouting constructing of the shield tunnel have a rather considerable longitudinal moment and axial force.The segments begin to crack and emerge dislocation. The security coefficient of the bolts reduces. As well, the soil of the vault segments have a big settlement. The research results can be taken example by the construction of the shield tunnel to make a reference function.