The invention discloses a method for preparing oligomeric proanthocyanidins by enhanced degradation under a pulsed electric field. According to the method, polymeric proanthocyanidins serving as raw materials are degraded under the assistance of the pulsed electric field to prepare the oligomeric proanthocyanidins. The method comprises the following steps of: dissolving the polymeric proanthocyanidins, adding sulfite, treating by the pulsed electric field, separating, performing alcohol leaching to remove impurities, purifying, concentrating and drying to obtain the oligomeric proanthocyanidins, wherein in the step of treating by the pulsed electric field, a polymeric proanthocyanidin solution is pumped in a pulse treatment chamber and is treated for 3 to 20 milliseconds under the conditions that the electric field intensity is 40 to 60 kV/cm, the pulse width is 50 to 120 microseconds and the pulse frequency is 100 to 3,000 Hz, and a pulse waveform is a square wave. The method is feasible, short in treatment time of the electric field, high in practicality, energy-saving and environment-friendly, so that the application range of the polymeric proanthocyanidins in fields of medicines, food, cosmetics and health-card products is expanded.