The purpose of this paper is to study the effect of excavation sequence of three-hole parallel shield tunnel on surface settlement and segment convergence, this paper conducts theoretical analysis and numerical simulation to find the optimal excavation sequence of three-hole parallel shield tunnel. Firstly, a "three-stage analysis method" is proposed to calculate the surface settlement of the three-hole parallel tunnel. This method is based on Peck’s formula and uses the first tunnel monitoring values as the base data to obtain the single tunnel surface settlement curve. The additional settlement curve is determined by the relationship between the repeat disturbance range and the line spacing. The single tunnel settlement curve and the additional settlement curve are offset and superimposed to obtain the total settlement curve. Then, using a shield interval in Jiangsu, China as the engineering background, FLAC3D was used to simulate the three-hole parallel shield tunnel in "right-center-left", "right-left-center", "center-left-right ", "right-center (reverse)-left", and analyze the surface deformation law and segment deformation law caused by these four working conditions. For the surface settlement law, it is found that the width of settlement trough caused by different excavation sequences is basically the same. However, there are differences in the maximum settlement values caused by the ground surface. The maximum settlement value obtained by numerical simulation is -11.8 mm, while the maximum settlement value predicted by the formula of "three-stage analysis method" is -11.66 mm, and the error is 1.46% and 0.25% respectively compared with the maximum settlement value of -11.63 mm obtained by fitting the measured fitting data. For the segment deformation law, the tunnel deformation caused by different excavation sequences changed from the standard circular shape to an ellipse with flat top and bottom and wide ends. However, there are differences in the offset process and the final segment convergence values. To integrate the surface settlement and segment convergence offset, and to consider economic factors such as construction efficiency and efficiency, the excavation sequence selection in the actual construction process gives priority to the excavation sequence of Case 4, i.e., the three tunnels are excavated in S-shaped sequence. The second choice is Case 1, i.e., the three tunnels are excavated sequentially. It can provide reference for the actual construction.