In order to analyze the mechanism of chiral signal enhancement of spherical particles, the Mie scattering characteristics of spherical particles are studied based on the T-matrix method, and the mechanism of chiral signal enhancement is analyzed based on the regulation of incident beam with orbital angular momentum (OAM) and particle’s characteristic parameters. The wave front of tightly focused linearly polarized light is regulated, the dichroism of OAM is measured by regulating the sign of OAM carried by the beam, and the relationship between the order of OAM and the intensity of the chiral signal is studied. When the order of the OAM carried by the beam is matched with the size of the sphere, the scattering circular dichroism signal can be enhanced by 22.8 times compared to that of circularly polarized light. The influence of particle size and chiral parameters on OAM dichroism signal is also analyzed.