In this paper,a vortex beam with different topological charges is generated by using a reflected type phase only liquid crystal spatial light modulator(LCSLM),and the interference characteristics of a vortex beam and a plane wave and a spherical wave are analyzed.When the CCD′s location is away from the image plane,there is a dark core in the vortex center.An increment of topological charge results in increasing diameter of the dark core.Experiment and theoretical analysis are consistent.Experimental results show that using the LCSLM,vortex beams with different topological charges can be generated dynamically in real time.The energy conversion efficiency is up to 60%.