Abstract: To study the influence of the web opening and cavity types on the mechanical performance of concrete cavity floors, two full-scale tests were carried out on the full-scale steel mesh box cavity floor (SMB floor) and on the concrete assembly box cavity floor (CAB floor) under a normal service limit state, and the crack patterns and load-displacement curves of the cavity floor were obtained. In addition, considering the effect of the web opening and the section shape, the modified equivalent plate method and the cross beam method, the numerical methods were established to analyze the mechanical behavior of two concrete hollow floors. Experimental results show that the cross cracks appeared at the bottom surface of two full-scale floors, that local inclined cracks easily appeared on the bottom surface of the cavity with the opening, and that local irregular cracks appeared on the bottom surface of the cavity without the opening. Lots of the flexural cracks appeared on the bottom surface of the edge beam, as well as the inclined cracks near to the joint region of the edge beams. Lots of parallel cracks appeared on the upper height of the column. The opening of the beam and the cavity has important effect on its local crack width and distribution. The increased height of the cavity and the edge beam led to the lower deflection of the floor. Compared to the analog cross beam method, the displacements obtained from the modified analogue slab method were conformed to the experimental results. T-shaped (inverted L-shaped) section pattern was suggested to calculate the bending stiffness of the rib (edge) beam.