The utility model provides a tunnel invert landing stage prevent guardrail bar, includes invert trestle (1) both sides along the preventing of invert trestle (1) length setting guardrail bar (2) and hydraulic system (7), prevents that guardrail bar (2) include one or more railing monomer, the railing monomer includes and is provided with between adjacent telescoping mast (4) flexible pneumatic cylinder (3) in one horizontal pole (5), the telescoping mast more than two or two (4), flexible pneumatic cylinder (3) be connected with hydraulic system (7), telescoping mast (4) and flexible pneumaticcylinder (3) equal vertical welded fastening is in the side of invert trestle (1), the top in flexible pneumatic cylinder (3) and telescoping mast (4) is fixed in horizontal pole (5). Simple structure, the construction is simple and convenient, originally, prevent that guardrail bar can contract from top to bottom, and sound construction, security are reliable, have stronger suitability to the excavation length of different inverted archs.