Abstract: Bending of concrete filled steel tubular(CFST)dumbbell-shaped beams is studied experimentally. Two types of cross sections of beams are discussed. One is the traditional type with concrete-filled in the web space, the other is a new type without concrete in it. Experimental results show that the CFST dumbbell-shaped beam has favorable elastoplastic and ductile properties. It can bear load even when the deflection reaches one-twentieth of its span. The concrete in the steel web has some influence on the local behavior of the web, but has very small influence on the overall behavior of the beam.