We analyze, separately, the effects of the microwave magnetic field and the oblique microwave field on multipactor discharge on a dielectric surface. Using particle-in-cell/Monte Carlo simulation, we obtain the temporal evolution of the number of electrons, direct current electric field, mean kinetic energy of electrons，and power deposited in the dielectric in the cases of the microwave magnetic field and the oblique microwave field. The numerical results show that the oblique microwave field and the microwave magnetic field can significantly affect the mean kinetic energy of electrons, but do not qualitatively change the number of electrons and the power deposited in the dielectric, so the microwave magnetic field and the oblique microwave field do not significantly affect the multipactor.