Based on the extended Huygens-Fresnel principle and Rayleigh scattering theory,analytical expressions of the optical radiation forces on Rayleigh dielectric spheres exerted by a focused partially coherent flat-topped vortex (PCFTV) beam are derived.The capture effect of the PCFTV beams on two kinds of particles with different refractive indices is mainly studied.The results show that the focused PCFTV beam could be adopted to capture high and low refractive index of particles near the focus.As the beam order decreases,or the correlation length increases,the ability of the beam for trapping particles increases.The results are expected to be useful for studying the trapping capacity of PCFTV beams applied in optical manipulation.