Screw drilling tools are mainly composed of four major assemblies: bypass valve, hydraulic motor, cardan shaft and transmission shaft. The screw motor is the main component of the drilling tool. Many practical and theoretical analysis results show that if the motor is to work normally and effectively, the pressure drop that each stage of the motor can withstand should not exceed 0.8Mpa, otherwise the motor will have leakage. The speed will decrease quickly, and in severe cases, it will stop rotating completely and the motor will be damaged. (One lead of the motor is one level) The mud flow rate used on site should be within the recommended range, otherwise it will affect the motor efficiency and even increase wear. The performance parameters of screw motors are the main performance parameters of screw drilling tools. The theoretical output torque of the motor is proportional to the motor pressure drop, and the output revolutions are proportional to the input mud flow. As the load increases, the drilling tool revolutions decrease, so as long as the reading of the pressure gauge on the ground and the flow rate of the pump are controlled, Control the torque and rotational speed of downhole drilling tools. The function of the transmission shaft is to transmit the rotational power of the motor to the drill bit, and at the same time bear the axial and radial loads generated by the drilling pressure. The drilling tool drive shaft structure manufactured by our company (shown in Figure 7) has applied for a national patent and has many advantages such as longer life and higher load-bearing capacity.