Metasurfaces have demonstrated their sensing capabilities in the terahertz (THz) region. However, the practical application of these technologies is constrained by the complexity of their structural design and the randomness of their sensing performance. In this work, we propose a novel THz sensor based on a surface lattice resonance (SLR) metasurface with high refractive index (RI) sensitivity (502.8 GHz/RIU), high-quality factor (Q) (164.4), and simple structural design. The high sensing performance is attributed to the SLR generated by the coupling of Rayleigh anomaly (RA) diffraction and spoof localized surface plasmons in the metasurface. In the experiment, 0.9 % (0.1538 mol/L) sodium chloride (NaCl) solution with human physiological concentration can cause a 246.8 GHz shift of the SLR peak. Furthermore, the sensor demonstrates a blue-shift of the SLR peak with the decrease of the structural period of the metasurface, and meanwhile, its RI sensitivity increases with regularity. This work provides a new method for detecting health indicators of human physiological concentration by designing highly sensitive THz metasurface for a specific frequency.