Abstract: According to the current trend of industry production, a new type of precast steel-concrete laminated slab is developed in order to solve the problems of large weight and complex procedure of rib pouring of traditional precast ribbed laminated slab. The mid-span deflections of traditional ribbed slab and steel-concrete laminated slab in the construction phase were analyzed by using ABAQUS. Meanwhile, the influences of rib’s height and the width of flange on the mid-span deflection of new laminated slab were also studied. In addition, the load versus mid-span deflection curves, the ultimate bearing capacity and the ductility of the two precast slabs were compared, and the influence of different dimensions on the mechanical properties of the new laminated slabs was analyzed. The results showed that the deflection of new laminated slab was less than that of the traditional ribbed slab in the construction phase when the width of flange was more than 30 mm. The mid-span deflection of new ribbed slab decreased with the increase of rib’s height and the width of flange. Compared with traditional laminated slab, the stiffness degradation of new type of laminated slab was slower after the longitudinal bars yielded. Furthermore, it had higher ultimate bearing capacity and ductility. Increasing rib’s height and the width of flange could effectively improve the ultimate bearing capacity and ductility of new laminated slab.