Abstract: Since the horizontal convergence of a shield tunnel is directly related to tunnel safety, AFRP (Aramid Fiber Reinforced Polymer) reinforcement is one of the commonly used treatment methods for deformation. In this paper, its mechanism and effects are discussed using a numerical simulation based on the horizontal convergence and joint opening, and the influence of AFRP pasting time and number of layers on the effects of reinforcement are analyzed in light of related parameters. The results show that: AFRP reinforcement can effectively restrict horizontal convergence and joint deformation, but the reinforcement effect is affected by the extent of tunnel deformation, i.e., the smaller the deformation, the better the reinforcement; and the reinforcement effect may increase significantly with an increase in the AFRP layers, with 2~3 being the best choice for layer numbers.