Abstract: A new type of lightweight composite pavement slab was developed to meet the weight reduction requirement of the main girder of the long span suspension bridge, and was successfully applied to the Yangsigang Yangtze River Bridge in Wuhan. Experimental, theoretical and finite element methods were used to study the mechanical behavior of the lightweight composite pavement slab, and the rapid assembly process was designed. The counterweight was used to simulate the response of the composite pavement slab under the crowd load, and the mid-span deflection of the compo-site slab was only 9.14% of the limit value of deflection. Three-point bending tests were carried out on three lightweight composite pavement slabs with different spans. The results show that the failure mode of the three specimens is basically panel yield failure, the ultimate bearing capacity of the largest span member YSG-TB-960 is the smallest (14.79 kN) , and the ultimate bearing capacity in shearing test is 28.68 kN. The 3D model of composite pavement slab was established by ANSYS/Multiphysics software and the finite element analysis was carried out to simulate the response of composite pavement slab under crowd load and concentrated load. The results of finite element analysis are in good agreement with the experimental data. The minimum error between the theoretical results and the experimental results is –7.73% when the ultimate bearing capacity is calculated by theory. The performance of the composite pavement slab was evaluated, and the minimum safety factor of the lightweight composite pavement slab is 10.42. All the components meet the design requirements.