The invention belongs to the field of coal mining, and particularly relates to a coal seam deep-hole high-energy pulse section-by-section step-by-step fracturing method. The method solves the problemsin the prior art that a high-pressure expansion fluid generated by a high-energy gas fracturing device acts on an entire fracture hole at the same time, and a hydraulic fracturing method causes wasteof resources easily. A device constructed by the method can be reused, cannot cause waste of water resources, cannot pollute the groundwater layer due to chemical substances, is economical and environmentally friendly, has high cost performance, and can be effectively controlled to perform controllable fracturing with controllable fracturing time and adjustable pressure value on coal seams of different conditions by obtaining the pressure release time and pressure value of a gas pressure generator through the selection of membrane rupture pieces of different specifications and calculation; the method can perform section-by-section controllable reservoir modification on the coal seams under different coal structure environments according to the crack development degree, and an existing coal seam fracturing process is improved.