This paper takes Yakang high-speed Qiantuai No.3 tunnel over the fault fragmentation zone as the engineering background,analyses the deformation characteristics of the surrounding rock through on-site investigation,establishes a three-dimensional model using numerical software,analyses the influence of different support parameters of the initial support on the deformation of the surrounding rock of the tunnel,and determines the reasonable support parameters.After adopting the optimised support scheme,the maximum subsidence of the vault reaches 154.3mm,and the convergence of the upper,middle and lower steps reaches 112.8mm,144.5mm and 79.8mm,respectively,and the deformation of the tunnel surrounding rock is effectively controlled.The research results provide reference for the deformation control and support scheme optimisation of similar projects.