Magnesium oxide film has high secondary electron emission yield and is found as applications in flat panel display widely. In this work, MgO nanowire electron emission properties, including both secondary and field emissions, are reported. MgO nanowire thin films have been synthesized on stainless steel substrate by thermal vapor deposition. The turn-on field of 9 MV/m for the field emission is measured with the MgO nanowire thin film, and the maximum secondary electron emission (SEE) yield of 8.3 is obtained. In addition, the good stability of SEE yield is also observed under long-time electron bombardment.