In order to solve the problem of insufficient matching between engineering analogy method and field construction, the design and optimization of system anchor rod have differences and contradictions in engineering practice. In order to improve the fineness of the bolt optimization of the initial support system of the tunnel, the Jiangyu Expressway Xiangshu'ao Tunnel was relied on. The system bolts were studied by numerical simulation to clarify the sensitivity differences of the system bolt parameters in each area of the cross section. The research results show that the main influencing factors of surrounding rock deformation are the length, diameter, circumferential spacing, and longitudinal spacing of the system bolts; The system bolts’ sensitivity to surrounding rock deformation is sorted in order of circumferential spacing, longitudinal spacing, diameter and length; Changing the system bolt parameters has a greater impact on the stress and strain extremes of the surrounding rock, while the impact on the stress and strain distribution characteristics is negligible; The optimization system bolt parameters improve its own loading characteristics more than other components, and its maximum improvement effect can reach 3.17 times that of other components. Similar projects can be used for reference from the research results.