The invention discloses a rotary assembly mechanism which comprises a support, a drive assembly arranged on the support and a rotary table assembly. The rotary table assembly is connected with a suction disc assembly. The support is further provided with multiple supporting assemblies for abutting against products. Each supporting assembly comprises a jacking air cylinder and a jacking air cylinder connection plate connected with the jacking air cylinder. Jacking air cylinder connection plates are provided with jacking guide sleeves. The jacking guide sleeves are internally provided with jacking guide columns. The top ends of the jacking guide columns are provided with supporting blocks. The jacking guide columns are sleeved with springs. The two ends of the springs abut against the supporting blocks and the jacking guide sleeves respectively. According to the rotary assembly mechanism, the multiple supporting assemblies for abutting against a mesh enclosure are arranged beside the suction disc assembly, and supporting of the mesh enclosure by the suction disc assembly can be enhanced, so that the stress of the mesh enclosure is more balanced and more stable in the rotating process, and swinging and falling conditions are avoided.