In view of that the construction period of shield crossing beneath high-speed rail is apt to cause soil deformation and large differential settlement of ballastless track plate and of the long-term implications on the tunnel structure of the train cycle dynamic load in operating period, with the project of shield crossing intercity in Suzhou as example, the paper determines pre-reinforcement method before crossing project, applies numerical simulation to analyze the influence of pre-reinforcement on the tunnel itself and surrounding strata, then derives the rule of pre-reinforcement on reducing soil deformation and tunnel internal force. The research gives that grouting in main and secondary reinforcement area will apparently reduce settlement deformation , jet grouting pile controls surface deformation well and soil pre-reinforcement will reduce a lot of shield tunnel segment internal force caused by high-speed rail operation.