The invention discloses an underground multi-stage intelligent high pressure gas pulse formation fracturing device and a method thereof, belongs to the technical field of fracturing completion of oil and gas wells, and particularly relates to two technical sachems of the device and the method. The method is used for fracturing the underground layer by the underground multi-stage intelligent high pressure gas pulse formation fracturing device. The device is controlled by each stage of intelligent pressure encoding detonator to gradually detonate by stages at proper time to generate a large amount of high pressure gas according to the set working mode, the dynamic high pressure pulse pressure is formed in the well or holes of a formation, the formation is fractured to form a plurality of cracks, and the permeability of fluid in the formation is increased, so the oil and gas are easily produced. The device and the method have the advantages that the cyclic multiple pressure pulses which are controlled at proper pressure can be generated, so the formation can generate the compression-expansion-compression alternating 'resonance', the cracks are promoted to effectively extend, and a new fracturing network is formed, so the permeability of the formation is improved; the pollution to the formation and environment in the fracturing process is avoided; the method is suitable for the water-sensitive and acid-sensitive formation; the construction cycle is short, the cost is low, the equipment is simple and convenient, and the limitation by terrain and water sources is avoided.