White oyster mushroom (Pleurotus ostreatus) is a food product that is easily damaged and has a short shelf life of 1-2 days. The production of oyster mushrooms in Indonesia is increasing every year so that an alternative is needed to maintain the shelf life of mushrooms. One technology that is still developing is plasma ozone technology. This technology uses cold plasma to produce ozone (O3). Recently, several researchers have developed ozone technology to maintain shelf life in post-harvest horticultural products. This study aims to determine the effect of storing white oyster mushrooms (Pleurotus ostreatus) with ozone plasma technology generated by the Double Dielectric Barrier Discharge Plasma (DDBDP) technique. The results of the ozone concentration in this study were 65 ppm with an ozone capacity of 5.85 grams/hour at a flowrate of 1.5 (L/min) and a voltage of 9.5 Kv. Ozone was flowed into a plastic containing mushroom samples in the treatment (5,10,15, 20 and 25) minutes. Based on the results of the shrinkage change test carried out, it was found that the shrinkage change was not too significant and decreased in the 20 minute and 25 minute ozone treatment