<p>Tunnel lining is a reinforced concrete structure that is the main load-bearing structure to support the pressure of the surrounding rock. The poor contact quality between tunnel lining and surrounding rock is a common tunnel quality defect and an important cause of tunnel structural diseases, directly affecting the safety of the tunnel structure. Thus, it is important to detect the adhesive quality behind the tunnel lining rapidly and accurately. The calculation of ultrasound travel time may be complex due to differences in the material properties of concrete and surrounding rock. Ultrasound imaging technology has been developed for precise and rapid imaging of defects in tunnel lining. In this paper, a fast multi-layer ray tracing (FMRT) combining Snell’s law and Fermat’s principle is proposed to identify the adhesive quality. The method establishes the relationship between imaging points and ultrasound propagation paths by traversing a local range of refractive points. Both the finite element simulation and experiments validate it can qualitatively distinguish three different adhesive quality, such as tight contact state, loose contact state and void between the concrete slab and the surrounding rock. The imaging efficiency of FMRT has been improved compared with minimum travel-time ray tracing (MTRT), which traverses all refractive points to specify a path with the shortest wave transition time. Furthermore, the imaging accuracy of ray tracing is superior to the traditional total focusing method (TFM) using a constant ultrasound velocity. This study can provide valuable suggestions for improving detection efficiency and imaging accuracy in identifying the adhesive quality behind tunnel lining.</p>