In order to study the fluid flow and heat transfer process of paramagnetic medium in the high temperature environment, in this paper, the radiation effect on the thermo-magnetic convection in participating paramagnetic medium under gravity condition is studied numerically. The external magnetic field with non-uniform magnetic gradient is imposed. For a paramagnetic fluid, the magnetic force is proportional to the product of magnetic susceptibility and the gradient of the square of the magnetic induction, and acts on fluid particles cooperatively with gravity. The magnetic susceptibility is related to absolute temperature according to Curie′s law. The thermo-magnetic convection is carried out in high temperature environment and the paramagnetic fluid is a semitransparent gray medium which absorbs and emits energy. In the present study, the distribution characteristics and the regularities of fluid flow, temperature field and average Nusselt number are investigated under different magnetic Rayleigh number and optical thickness. The research results show that the magnetic field and radiation could enhance the convection, but have suppression effect with the increasement of optical thickness.