According to experiment, spraying cold boiled water on Oyster mushrooms facilitates increasing at least 25% of yield. The specific method is to spray 2kg of cold boiled water on fungi bed or fungi sack in each square meter, make it once a day and continue for 2 days when spawns are fully-grown. When coralliform primordiums massively appear, spray cold boiled water on fungi bed or fungi sack for 3 times per day and each square meter spray 1.5kg. However, water should be refused one day before the picking and within 3 days after the picking.