The thread gluing, bending and fracture of conventional drill pipe often occur during large diameter long horizontal directional borehole drilling at the high position of coal mine roof. The analysis is made on the working state of drill string and the stress mode of drill string and finite element analysis mode are established, the main reasons of pipe failure is defined. By optimizing thread tooth type and joint connection form, φ73 drill pipe is developed with high toughness and strength, which can overcome drill pipe rupture, thread gluing and some other disadvantages to meet the requirements of large diameter long horizontal directional borehole drilling construction at high position of coal mine roof.