In order to investigate the mechanical behavior of continuous composite beams with web openings, six composite beams,in which five with openings and one without web openings, were studied. The research contents include three parts as follows: bearing capacity and shear distribution of composite beams in the hole process of loading. The results show that: compared with beams without web openings, beams with web openings have a significant decrease in load carrying capacity; The shear force at the cross-section of a concrete slabs increasing with the increase of load in the web openings region, but the shear force at the cross-section of a steel beam is more larger than a concrete slabs in the region of beams without web opening. It also shows that the relevant provisions of shear calculation in Code for Design of Steel Structures can not meet of beams with web openings already.