In response to the shortcomings in the construction of temporary support for tunnels, a assembly of temporary support was proposed, and the new structure was studied from the aspects of temporary support shape, assembly structure, and stress deformation. Taking the Shaojiatang Tunnel as the background, on-site monitoring data was collected and compared with traditional temporary support structures using finite element software. It can be concluded that excavation of the tunnel's rear tunnel will have adverse effects on the deformation of the previous tunnel. Vertical temporary support has better control over the left and right arch waists, surface settlement, and total convergence deformation of the tunnel. Compared with traditional curved structures, it decreases by 16%, 20%, 55%, and 14%, respectively. Moreover, vertical temporary support can restore stability faster and shorten the dismantling distance. By using vertical temporary support, the initial support force of the tunnel is smaller and safer compared to the curved support, and the maximum vertical and lateral stresses are reduced by 58% and 73%, respectively. The mechanical characteristics of temporary support local structures were simulated using ABAQUS software. The results show that the forces and deformations of both prefabricated vertical and traditional temporary support structures can meet the requirements of the specifications. However, prefabricated temporary support structures have more advantages in construction efficiency and economic benefits, and choosing prefabricated temporary support is more suitable.