Precast concrete (PC) plays an important role in the industrialization processes of buildings, so it is critical to study the seismic performance of such structures. Several experimental and numerical studies have been conducted to investigate the behavior of PC beam-to-column connections. However, most of the previous studies neglect the contribution of slabs. In light of this, this paper presents a numerical simulation method for dry connected beam-slab assemblies based on the layered shell element available in OpenSees. The beams were modeled with fiber elements, while the slabs were modeled with layered shell elements. The developed model was validated by simulating a typical beam-slab assembly test, with the characteristics of hysteretic performance found to be well reflected by the model. Moreover, a parametric study was performed to quantify the influence of slab parameters. The results showed that the thickness of the slab had a significant effect on the hysteretic performance of the specimen and that the influence of the slab width was obviously reduced after it exceeded a certain limit. Besides, the effect of the reinforcement ratio on stiffness and loadbearing capacity was not obvious and was accompanied by a slight positive correlation with the energy dissipation capacity.