In order to study the influence of seismic dynamic load on the mechanical property of large-span shallow buried and open-cut prefabricated structures, the Zhongshan underground utility tunnel project is taken as the background, a three-dimensional solid model of the soil-utility tunnel structure is established with the help of finite element software ABAQUS, and the influence of force and deformation of the prefabricated utility tunnel structure is simulated by adjusting the buried depth and acceleration peak (0.1g, 0.2g, 0.3g). The results show that: 1) Compared with the cast-in-situ structure, the maximum principal stress of the prefabricated structure increases by 33.75%, and the minimum principal stress increases by 12.63% compared with the cast-in-situ structure under the same seismic wave load; 2) the relative displacement fluctuation of the side wall and the middle wall of the cast-in-situ structure is smaller, while the fluctuation range of the prefabricated structure is larger; 3) the most unfavorable position of the structural stress is mainly located at the auxiliary angle where the tension side of the long-span bottom plate and the roof and the middle partition wall intersect, which should be focused on in the process of design and maintenance reinforcement. The results can provide references for similar structural design of large-span shallow buried and open-cut prefabricated utility tunnel.