The stability of the tunnel face is a big challenge when a tunnel with large crosssection is constructed in soft stratum with low cohesion. Numerical simulation is made for the excavation of Liuyanghe tunnel, which is constructed by prereinforcement method. By analyzing the impact of the prereinforcement on the displacement and forcebearing behavior of the tunnel and by studying the sensitivity of all the reinforcement parameters, the authors conclude that the reinforcement length of the advance anchor bolts has the greatest impact on the stability of the tunnel face and that the prereinforcement outside the perimeter of the tunnel also has great impact on the improvement of the forcebearing behavior of the advance core.