Abstract: To satisfy the construction safety of loess tunnels in special sections, it is important to strengthen the initial support to intervene in the stress state of surrounding rocks as soon as possible. Based on the exploration of a new support structure, this paper proposes the steel-concrete composite structure support system. By changing the stiffness ratio between the initial support and the secondary lining, the support strength can be provided at the initial stage of construction, so as to reduce the occurrence of loose pressure. ANSYS software is used to establish a threedimensional excavation model, the bearing characteristics and component parameters of the steel arch of the composite support structure are analyzed from the perspective of the overall and local forces, and the supporting performance is evaluated through comparison with the common support system. The results can provide reference for the study of the new support structure of loess tunnels.