The invention relates to a directional rotary directional drilling tool and a method for near-horizontal drilling in an underground coal mine. The directional rotary directional drilling tool is composed of a curved shell, a transmission shaft, a universal shaft, a rotary mandrel, a supporting and fixing system and a while-drilling measuring system. The rotary mandrel, the universal shaft and thetransmission shaft are sequentially connected in the curved shell, and the while-drilling measuring system comprises a nonmagnetic drill rod and a measurement probe pipe arranged inside the nonmagnetic drill rod. The supporting and fixing system comprises a plurality of telescopic wing ribs, a special-shaped piston and a spring. Therefore, the directional rotary directional drilling tool is simplein structure and fast and convenient to realize and can replace a bent screw to realize rotary directional drilling, and the power of the tool comes from the rotating torque of the drill rod, so thatthe problem of large friction resistance in sliding drilling is solved, the capability of a high-power directional drilling machine can be fully exerted to extend a drilling hole to a deep formationand improve directional drilling efficiency.