The invention discloses a method for preparing a biogenic biphase coating anti-staling agent for pickle stem tuber raw materials. The method comprises the following steps of: preparing an ethanol-water solution, regulating the pH value to be 6.1-6.6, and adding chitosan, propolis and porous starch into the ethanol-water solution based on the mass of the ethanol-water solution; adding natamycin, nisin and poly-L-lysine; and stirring by using an electric stirrer at constant temperature for 1 to 2 hours at a stirring rate of 900r/min, adding cinnamon oil, clove oil and rosemary oil, adding 1.0 to 3.0 percent of Tween-80 emulsifier, stirring by using the electric stirrer for 1 to 2 hours at a stirring rate of 1,200r/min to make the mixed oil uniformly dispersed, and homogenizing at a rate of 1.6*10<4>-2.0*10<4>r/min for 30 minutes to obtain the coating anti-staling agent. Product pollution because mixed bacteria are attached to the raw materials in the fermentation process is avoided, themature periods of pickle products are consistent, and product quality is stable.