Abstract：With the merits in road line and entrance location choosing，the proportion of twin tunnel is bigger and bigger compared with separated two single tunnels. According to the code for design of road tunnel，the tunnel¢s surrounding rock from supports in calculating for tunnel designing is separated；and the calculated results can¢t reflect construction stages reasonably. So it is necessary to make optimal analysis of construction schemes for twin tunnel. Considering the characteristics such as shallow，large span and double-arch of Longshan tunnel，a finite element analysis program for twin tunnel is established which can simulate the construction process under the three-pilot drift method and benching tunneling method；and the settlement of vault and ground，stress of the middle wall and the stability of the surrounding rock are compared and analyzed；then the advantages of the two methods are compared so as to optimize the practical construction scheme.
