Laguerre-Gaussian beams are typical vortex beams,the orbital angular momentum of the beam can be transmitted to the microsphere and make it do an orbital motion.The trapping forces exerted by the highly focused linearly polarized Laguerre-Gaussian beam (LGB) on a spherical particle are calculated by means of the T-matrix method and Maxwell stress tensor integral.The impact of microsphere radius and beam order on the particle′s trapping states in the vortex focusing field are investigated.When the topological charge keeps constant,with the microsphere′s radius increases,the trajectory of the orbital motion will gradually shrink.As its radius is larger than the critical value,the microsphere will be trapped on the optical axis without orbital motion.However,axial trapping forces of particles trapped off-axis are smaller an order of magnitude than those of particles trapped on axis,so that more input optical power is needed to maintain the stable orbital motion.