Abstract: There are many disputes about the effect of systematic bolts in tunnels, especially in weak surrounding rocks. One point of view is that the system bolts can reduce the deformation of the surrounding rocks, and the supporting effect is good, in particular, the side wall bolts can play a better supporting and restraining role. On the contrary, it is considered that the system bolts has no obvious effect, and the application of the system bolts delays the best time of initial support and leads to the increase of the surrounding rock deformation, but the surrounding rock deformation and stress condition are good after the removal of the system bolts. Based on the Ⅳ-level soft surrounding rock section of the Lijiazhai tunnel under construction in the Guizhou Yan-Yin-Song expressway project, a lot of field tests are carried out on the effect of systematic bolts. Three measurement sections are set under every condition, with and without the system anchoring bolts. The measurement includes pressure stress of the surrounding rock, both inside and outside stress of steel frame, axial force of systematic bolts, internal stress of jet concrete, settlement of tunnel crown, and horizontal convergence, etc. The test data of the comparative test sections and engineering verification indicate that (1) as the closure time of the initial support is prolonged by using the system bolts in tunnel, the surrounding rock pressure and steel frame stress are slightly larger than that without the rock bolts. Whether the tunnel is equipped with the system bolts, there is no obvious difference in the deformation and stress of the surrounding rock, so elimination of the system bolts will not affect the safety of the supporting structure. (2) As most of the systematic bolts are under pressure, the effect of the system bolts is poor. Obviously, the measures of application of the system bolts are too conservative, and there is a lot of room for optimization. However, the side wall bolts of the tunnel can play the role of the feet-lock bolts. When cancelling the system bolts, the feet-lock bolts should make sure to use. (3) The measures of erecting steel arches and cancelling the system anchoring bolts in the supporting structure in the Ⅳ-level soft surrounding rock section of the Lijiazhai tunnel can guarantee the initial support structure stability, and are technically safe and feasible.