Nitrogen is the important element for plants to live, and it just can be absorbed by plants in the simpler compounds form, which is nitrate. Plasma Electrolysis is a technology for the synthesis of new materials with the reactive species such as hydroxyl radicals and electrons are produced, including fixation of nitrogen from the air into nitrate solutions, which is the liquid fertilizer for plants. This research aims to determine how the nitrate solution can be formed through Plasma Electrolysis process and the influence of air flow rate as its raw material. The process is carried out at optimum power obtained from the results of plasma electrolysis current-voltage characterization. The concentration of nitrate formed was tested quantitatively using the UV-Vis spectrophotometry method. The results of this research show that the greater the air flow rate increase the nitrate productivity, but the specific energy consumption needed is decrease. Nitrate formed is able to reach 636.8 ppm at the highest air flow rate, which is 0.8 lpm. These results indicate that nitrates can be produced effectively by the Plasma Electrolysis method.