DS E-MWD uses low-frequency electromagnetic waves to transmit wellbore trajectory data to the ground. It realizes real-time monitoring and guidance control of drilling operations. Electromagnetic wave transmission will not be affected by fluid properties, and it has fast transmission speed, which can up to 10bps. This system is suitable for gas drilling and underbalanced air drilling. The launch frequency of downhole system can be set. There is no moving parts underground. And it has the advantages of low maintenance costs and long service life