The invention discloses a method for extracting punicalagin from pomegranate bark. The method includes the following steps that 1) the pomegranate bark is used as a raw material, reflux extraction is conducted by using a 10%-30% ethanol solution, an extracting solution is concentrated, by the aid of macroporous resin, the macroporous resin is washed, then a 20%-30% ethanol solution is used for conducting elution, the eluant is collected, concentrated and dried, and then a crude extract is obtained; 2) the fluid which is formed by dimethyl ether, liquid ammonia and dimethylamine according to the weight ratio of 7-9 : 2-4 : 1-3 is used as an extraction agent, subcritical extraction is conducted on the crude extract, the injection rate of the extraction agent is once or twice of the weight of the crude extract, the extraction temperature is 28-31 DEG C, the extraction pressure is 1.2-1.6MPa, the extraction time is 25-45min, and after the self-volatilized extraction agent is recycled, a finished product is obtained. According to the method for extracting the punicalagin from the pomegranate bark, when reflux extraction and macroporous resin washing are carried out, a low concentration ethanol solution is selected, the punicalagin can be better extracted, afterwards, further subcritical extraction is conducted, the time is short, operation is achieved at one step, product yield and quality are high, and therefore the method is more suitable for industrial production.