Abstract: Due to the high density of bus floor,a PU foam sandwich which was designed was used as a low density bus floor.To meet the new requirements for the bus floor,a new and light bus floor,with the optimized structure of PU foam sandwich,has been developed.The density of PU foam should be controlled at about 450 kg/m³,and the reinforced layers are made from glass fiber reinforced microcellular PU.The screw holding capacity of the floor is up to 1 080 N.