The invention discloses a novel gas phase fracturing roof weakening treatment and safety caving method which comprises the following steps: (a) obliquely upwards drilling a pre-splitting hole in a coal seam roof by virtue of the design angle and different drilling hole distances by using a ZLJ-350 special underground drill rig for coal mine from the open-off cut of the coal face and an air return and inlet down channel which is 20-30m away from the open-off cut, wherein the diameter of the drill hole is 75mm; (b) pushing a fracturing rod, wherein after the drilling construction is finished, the drilling and pore-forming effect is observed, namely whether the conditions that the hole collapses and the hole is blocked by coal and gangue is observed, and if the hole collapse and hoe blockage conditions occur, workers are timely organized to clean; then, in order to accelerate the construction progress, on the basis that the mass and friction resistance of the fracturing rod are calculated, each drill hole needs to be pushed by 4-6 workers and a technician by utilizing manual push, and the number of the persons pushing the fracturing rod in the hole is properly adjusted according to the depth of the drill hole; and (c) connecting and blasting, namely connecting a blasting line from the interior of the hole to the safe distance outside the pre-splitting hole and performing pre-splitting blasting.