Abstract: In the crack depth inspection and re-inspection after repair in tunnel lining, there are frequently fillings in the crack such as water, sand, cement slurry, crack grouting resin filler and so on, which may affect the inspection result. Relying on the Third-party Quality Inspection Test Center of De-Shang highway exploratory test of crack depth inspection and based on the results of exploratory test and engineering example, this paper researches the influence of filling on the inspection result. It is valuable to improve the accuracy of results of cracks depth inspection and re-inspection after repair.