A slotting induced-flow pressure-relief anti-reflection method for a complicated seam is suitable for gas control of high-gas high-ground-stress complicated seam regions, can improve the gas permeability and gas desorption rate of coal, solves the difficult problems of low exhausting and mining efficiencies of coal-bed gas, high drilling construction load and the like, and realizes efficient gas exhausting and mining as well as fast outburst elimination of the complicated seam. High-pressure water is jetted into drilled holes to cut and destroy the coal in a rotary manner, and the coal in the radial direction of the drilled holes is destroyed and disturbed, so that buckling failures of the coal are induced and the coal and the gas are enabled to be spouted out of the drilled holes, as a result, the gas expansion energy of the coal is released, coal cracks are expanded and the exposure surface area of the coal is increased. therefore, the gas exhausting and mining efficiencies of coal are improved, coal and gas burst risks are eliminated, the effective influence range of drilling gas exhausting and mining is improved by 1-3 times, the air permeability coefficient of coal around the drilled holes is improved by 100-200 times, the drilling methane gas exhausting and mining quantity is improved by 2-5 times within hundreds of meters, and the outburst elimination time of the coal bed is shortened by 30-50 percent. The slotting induced-flow pressure-relief anti-reflection method for the complicated seam has very good field application value and social benefits.