Based on the actual situation of field monitoring of tunnel in expressway, the displacement back analysis method is adopted, and the Geo-Inverse. m program is used to compare the data obtained from the analysis with the actual monitoring results. The two parameters of horizontal convergence and vault settlement are comprehensively compared. The results show that the maximum peak values of vault settlement and horizontal convergence are 15.4 mm and 14.4 mm respectively, and the differences between the measured results and the inversion results are 0.4 mm and 0.28 mm respectively. The basic parameters of surrounding rock of tunnel are elastic modulus 1.50 GPa, Poisson 's ratio 0.35, cohesion 350 kPa, which indicates that the surrounding rock is weak, but it can reach a stable state after support. The research results have certain reference significance in tunnel surrounding rock inversion.