The generation and interference of vortex beam have been investigated both theoretically and experimentally in this paper. The interference pattern of fractional and integral vortex beams with vortex beams with spherical wave and plane wave have been studied numerically, and the corresponding experimental results are presented. The experimental results and numerical results are practically consistent. It is found that the interference pattern varies with the topological charge of vortex beams. This phenomenon can be used to detect the topological charge of fractional vortex beam.