The invention discloses a tunnel invert repair secondary lining reinforcing structure and a construction method and belongs to the technical field of tunnel construction. The construction method includes that a steel pipe anchor bar pile composed of a foot-locking anchor pipe and a bar bundle is inserted into a reinforcing hole at a corner of a secondary lining side wall, cement mortar is poured for reinforcing, and the steel pipe anchor bar pile penetrates secondary lining reinforced concrete and extends into surrounding rock, so that balance of an invert and integral structural of a tunnel after the invert is removed can be maintained effectively, inward sliding of the secondary lining structure and cracking are avoided, safety of construction personnel and equipment is ensured, construction progress is improved, project quality can be ensured greatly, and project life can be prolonged greatly.