This paper reviews the analytical strategy employed in conventional p-n junction. Then it goes through the analysis of magnetic p-n junction in the same strategy, which makes the review of magnetic p-n junction succinct. I-V equation of magnetic diode is the result of the p-n junction analysis. However, of great importance is to form an acceptable ohmic contact on magnetic diode, which is assumed to be ideal during the magnetic p-n junction analysis. The paper moves on to ohmic contact for magnetic diode, with the example of GaN based magnetic material. With the calculation of the shift of Fermi level in n-GaN with band splitting, conventional ohmic contact structure for n-GaN can be employed to magnetic n-GaN. Experiments from one group prove it. Ohmic contact optimization experiment on n-GaN is present. Ni/Au deposition on n-GaN shows an acceptable ohmic contact. The outlook part points out that the way for research on Schottky diode on magnetic material is partially paved by contents included in this paper.