In order to study the mechanical properties of the four-sided simply supported two-way laminated slab with shear keys, the test of the laminated slab was carried out and the feasibility of the finite element simulation method was verified based on the experimental results. By simulating the loading process of the laminated slab with different parameters, the distribution law of shear force of shear key and the influence factors on mechanical properties of laminated slab were analyzed, and the simplified calculation equations of yield bending moment and yield displacement were established. The results showed that a secondary concrete pouring phenomenon existed between the precast base plate and the shear key, between the precast base plate and the cast-in-place concrete. However, it still had a good integrity. Under the vertical uniform load, the shear key showed a brittle failure. Only when the number of shear keys in failure reached a certain extent could the laminated slab be failed. When the joint surface was set to the frictional contact mode, the yield load of the laminated slab increased and the yield displacement decreased with the increase of the number of rows of shear key, the number of columns and the cross-sectional area. When the three factors above increased to a certain extent, the influence was no longer obvious. For the two-way laminated slab with a certain number of shear keys, the strength grade of the concrete of the cast-in-place layer and shear key, and the friction coefficient of joint surface had little influence on the bearing capacity of the laminated slab. The simplified calculation equations established for the yield bending moment and yield displacement of the laminated slab with shear keys can be referenced in engineering.