By the radial horizontal jet drilling technology applied in oil industry, horizontal directional jet hole can be realized for water block grouting in coalmine. This technology can also be used in looking for the linked fractures in thin limestone and Ordovician limestone confined aquifer, especially in multi-branch injection in vertical well and multilateral well with slight leakage; what is more, with this technology adding appropriate amount of hydrochloric acid and acid corrosion inhibitor for local acid to fracture formation in order to reduce the grouting pressure and improve grouting effect for water blocking. The radial hydraulic jet drilling technology was applied in 9# grouting hole of Wutongzhuang mine of Fengfeng Group with some effects, which can be a means of increasing the water amount of geothermal well.