Abstract: During the construction process of half steel plate reinforced concrete (HSC) roofs, the structural gravity and construction loads are born by the steel plates in the roof, which are temporarily used as templates and braces. After the concrete hardens, the concrete, steel plates and reinforcing steel will collaboratively resist the external load through combined action. In this paper, the deactivation element and trace element techniques are applied to simulate the construction process of the HSC structures. Firstly, a numerical model of large-span HSC beam is developed to simulate the experiment on a typical component. The effectiveness of the numerical model is confirmed and the bond slip between concrete and steel plates is investigated via the simulation. Then, the deactivation element and trace element techniques are used based on the numerical model to study the mechanical properties of the one-time formed and the multi-step formed HSC beam specimens. The results show that the final bearing capacity and the initial stiffness of the specimen considering the construction process reduce slightly. The construction process primarily increases the final deformation of the specimen. Finally, the roof system is simulated to study its stress and deformation after construction process, providing a reference for the design of such roof structures.