Sodium chloride was used as main component for production of electrolytic water in this study. Washing treatment by using the electrolytic water was the major processing and its high oxidant ability or bactericidal ability would inhibit and kill the microorganism, in hope to extend the preservation period. The scallion (Allium fistulosum L.) at Sunshin area in Yilan County of Taiwan and water convolvulus (Ipomoea aquatica Forsk.) was selected in this study because the volatility of their price was easily influenced by typhoons and festivals. The experimental results indicated that the optimal preservation conditions for scallions were washed with 40 ppm electrolytic water (as ClO2 at 5°C) for 3 minutes and stored in the sealed polyethylene (PE) bags without ethylene absorbent at 5°C and the shelf life was able to reach to 3 weeks and very low yellowing or decaying index were performed. The optimal preservation conditions for water convolvulus were that 30 ppm electrolytic water (as ClO2 at 5°C) with ultrasonic spray washing for 5 minutes and stored in the PE bags without ethylene absorbent at 10°C and the shelf life was also able to reach to 21 days and kept visual quality.