The invention relates to the technical field of tunnel engineering and discloses a method for processing a grouting position of a hidden cave at the bottom of a tunnel. The processing method includes the steps that firstly, cave detection is conducted, wherein an advance geological forecast method is comprehensively used for determining the position of the cave at the bottom of the tunnel according to the position of the bottom of the tunnel, and the position where the hidden cave is detected is marked; secondly, a second hole site is designed, the position of a grouting hole is designed based on the first step according to the two-dimensional stress distribution condition around a round hole in an elastic flat plate; thirdly, grouting is conducted, jet grouting is conducted on the stress concentrated part of the hidden cave for strengthening; fourthly, grouting is conducted, a compaction grouting technology is used for filling a hidden cave body. According to the method for processing the grouting position of the hidden cave at the bottom of the tunnel, the two-dimensional stress distribution state around the round hole in the elastic flat plate serve as the theoretical basis, the defect that construction is conducted by mainly relying on experience in the past is overcome, the stability of tunnel surrounding rock on the upper portion of the hidden cave is ensured, and the normal operation of the rear stage of the tunnel is ensured.