In the process of electron beam and plasma interaction, the angular magnetic field produced by the electron beam affects the physical parameters of the plasma. In this paper, first, the Thomson ionization coefficient under the condition of cross field is derived. Second, based on a magnetohydrodynamics method, the axial distribution of plasma density in the positive column of low-pressure glow discharge under the magnetic field is deduced, and the effect of the angular magnetic field on glow discharge plasma is studied. Finally, the above results are verified by numerical simulation. The results show that when the pressure is 10 Pa, the plasma density first increases and then decreases with the increase of magnetic field. When the pressure is 0.1 Pa, the plasma density decreases with the increase of magnetic field.