Abstract: To solve the problems such as rock burst, gas accumulation and the low recovery rate of top coal during the initial mining of top coal caving mining caused by hard roof which is hard to break down, the design and field test of weakening roof at 3301 fully-mechanized caving face of Tang'an Coal Mine with the method of deep-hole pre-splitting blasting was set up. The results show that the optimal blasting parameters such as blast hole spacing, hole elevation were reasonable and the blasting can make the roof pre-splitting and change its stress state; the initial roof fracture step distance was shortened by 38.43 m, and the yield increased by 22 801 t. The caving of main roof in advance solves problems of rock burst and gas accumulation in gob result from ventilation difficulties.