The interference phenomenon of vortex beams and plane waves is analyzed. By using coaxial superposition interference of vortex beams, we can generate the light with binary orbital angular momentum, and apply it to the topological charge number detection of orbital angular momentum. We use fork dislocation grating to generate centrosymmetric vortex beams and then discuss the generation of light beams with binary orbital angular momentum by the interference of two vortex beams with different topological charge numbers. Numerical and experimental results show that with the change of the topological charge number value, either plus or minus, the interference image which is generated by the interference superposition of two vortex beams is also changing regularly. According to this, vortex beams can be detected. Moreover, vortex beam has important significance in information transmission and coding. Our study provides experiment basis for the reuse of vortex beams in free space communication, and provides potential for performance improvement of optical communication system.