During the top heading construction of Matijing tunnel on GanzhouLongyan railway, huge deformation occurs to the 30mlong exit portal section, which is followed by full collapse. Several treatment options are attempted, but unfortunately no success is achieved. After thorough geological investigations, it is determined that there exist landslide, on basis of which comprehensive treatment plan is prepared. The article presents the landslide treatment method, demonstrating the great importance of thorough geological investigations in tunnel engineering works.