The utility model relates to a heat insulation bearing floor plate for a steel structure building. The heat insulation bearing floor plate is formed by a high-intensity calcium silicate plate, a haycite lightweight aggregate concrete layer and a shear connector in a gapless-integral-composite mode. The high-intensity calcium silicate bottom face plate and the haycite lightweight aggregate concrete layer are integrally formed in a composite mode. A hole is formed in the high-intensity calcium silicate bottom face plate. A butterfly-shaped bolt is connected with a haycite lightweight aggregate concrete base body. Semi-grooves are formed in the upper portions of the four outer sides of a composite layer plate. A groove is formed after assembling and plate paving. The groove and a plate joint are filled with expanding polymer cement mortar. The technical problems that a profiled steel sheet and a reinforced concrete composite floor plate are used in an existing steel structure building, self weight is large, the steel using amount is large, on-site wet construction is complex, the construction time is long, and floor plate heat preservation performance is poor are solved.