In order to solve the problem of large-span bias tunnel construction process,and tunnels excavation influence with each other,the finite difference method was used to calculation and analyze the large-span bias small spacing tunnels construction process and space effect. The results show that whichever kind of excavation method,the tunnel stress have asymmetry,shared rock and the hence of large buried depth on one side is the stress concentration area,excavation shallow side first is more conducive to the stability of surrounding rock. When two tunnels were excavated at the same time,the tunnel face was beyond a certain range,that the mutual influence of two tunnels was small.