The field emission characteristics of an oxidized porous polysilicon were investigated using different oxidation process with Pt/Ti multi layer electrode. The surface oxidation layer on an oxidized porous polysilicon was formed by thermal oxidation and electrochemical oxidation. The emission efficiency of thermal oxidation which was performed in a dry O-2 with O-2 flow rate of 3/min at 900 degrees C for 60 min showed 3.36% at V-ps = 16 V. The electrochemical oxidation was formed by solution containing 1 M sulphuric acid under 10 mA/cm(2) for 40 sec and was annealed 5 hr to improve oxide quality at 600 degrees C. The emission efficiency of electrochemical oxidation showed 3.81% at V-ps = 14 V.