Abstract: A new type of plain steel-plate-concrete composite hollow slab is composed of common steel plate,internal hollow model and concrete connected with steel PBL shear connection.Due to the using of plain steel plate and internal hollow model,the composite slab has lots of advantage such as light-weight,sound-proofing and easy construction without bottom forms,therefore,this type of composite slab has wide prospect for projects.Experiments of six specimens of such composite slabs were conducted to study the mechanical behaviors.Based on the experimental results,the influences of the nominal shear-span of the slabs were studied.During the experimental process,the failure modes,concrete strains,types of cracking,interface slippage and bearing capacity of the decks were focused.From the experimental results,it could be found that no obvious slippage on the interface of between the steel plate and concrete were measured in the composite hollow decks,which result in big flexural rigidity,good ductility as well as good bearing capacity,indicating that the strengths of both the bottom steel plate and the top concrete were fully utilized.Calculation methods for the bend-bearing capacity of the composite decks were proposed.It could be concluded that this type of composite hollow slab was advantageous in mechanical behaviors,and should be more widely studied and applied.