The invention provides a high-pressure pneumatic blasting pressure relieving and transmission increasing method, comprising the steps of constructing a blasting 
drill hole in a 
coal layer, and carrying out high-pressure 
water jet seam 
cutting operation in the blasting 
drill hole at intervals, so that a lead seam groove is formed in a 
coal body around the blasting 
drill hole; feeding a blasting steel 
pipe with plugged top part into the blasting 
drill hole, forming a plurality of air vents at the front part of the blasting steel 
pipe, and sealing a section inside a hole opening of the blasting 
drill hole by 8-10 m, so as to form a 
cement plug; and connecting the blasting steel 
pipe with a high-pressure air 
station through a pipeline at the exposed end of the blasting steel pipe, and opening a valve arranged on the pipeline to inject high-pressure gas, so that the high-pressure gas is jetted by the blasting steel pipe from the air vents. On the basis of forming cracks and fractures formed in the fractures and 
cutting grooves of the original 
coal body, the high-pressure gas instantly impacts the blasting effect, so that the cracks and the fractures can be continuously expanded, and a lot of new fractures can be generated. Finally, a mutually communicated large fracture screen is formed in the coal body by using the blasting 
drill hole as a center, so that the purpose of pressure relief and transmission increase of the coal body can be realized. Furthermore, the high-pressure pneumatic blasting pressure relieving and transmission increasing method has the advantages of simple operation, easiness of realization and obvious effect.