Landslide may occur near the portal of a tunnel under construction. In the paper, the warning criterion for the landslide near the tunnel portal is determined according to the site conditions, and it is concluded that comprehensive early warning may be made for the landslide mainly according to the ground surface deformation, the horizontal displacement of the top of the antislide piles, the lateral stress of the antislide pile body and the rainfall. The paper can provide reference for the early warning of landslide of similar projects.