In present paper, we study the properties of the Killing magnetic field of a pseudo null magnetic curve in R_1^3 . We investigate for the T, N and B-magnetic cases of a pseudo null curve. We find the conditions for the Killing magnetic field to be pseudo null and derive the Frenet formulas for this field. Finally, we obtain the conditions for the transformation of the pseudo null curve to its pseudo null Killing magnetic field with equal torsions.