The invention discloses a karst cave treatment method for tunnel construction, and relates to the technical field of building construction. The problem that a treatment mode of medium and small-sized karst caves is insufficient in strength is solved. The karst cave treatment method for tunnel construction comprises the steps of S1, karst cave surveying, S2, grouting hole digging, S3, grouting steel frame mounting, S4, grouting treatment, and S5, later curing treatment. The karst cave treatment method for tunnel construction adopts a novel construction mode combining a grouting steel frame with concrete, the grouting steel frame is composed of an outer shell and a steel frame, the steel frame is arranged in the outer shell, and the steel frame comprises a transverse rod device I, a transverse rod device II, a transverse rod device III and a longitudinal rod, wherein the transverse rod device I, the transverse rod device II and the transverse rod device III are mounted on the longitudinal rod at equal distances. Through the karst cave treatment method for tunnel construction, the problem that the treatment method of the medium and small-sized karst caves is insufficient in strength is effectively solved, the strength of a rail construction base face is improved, and the possibility of foundation subsidence is decreased.