The paper is related to the most significant aspects of numerical simulations in seismic analysis of tunnels, highlighting the soil-structure interaction phenomenon. The modelling of a problem and analysis of relevant influences may be completed by an application of software packages based on the finite element method. In order to define a reliable and efficient numerical model, that should simultaneously put together both the criteria of simplicity and realistic presentation of a physical problem, analyses should start from the most simple modelling techniques (theory of elasticity, replacing the soil medium with elastic springs, pseudo-static analysis), with the final goal to accomplish a more complex and realistic model (theory of elasto-plasticity, finite element method, full dynamic analysis).