The EM-MWD tool is based on the transmission technology of electromagnetic waves in the formation, which real-time uploads the downhole measurement while drilling data to the surface. It has the advantages of being unaffected by drilling medium and high transmission rate. However, due to the significant impact of formation resistance of the communication path, the data transmission depth is limited, which restricts the development of EM-MWD tool. This article briefly introduces the system composition and working principle of the EM-MWD tool (DREMWD) independently developed by China Petroleum Engineering Technology Research Institute. It conducts in-depth research on downhole high-power generation technology and front-end amplification circuit, further enhancing the downhole signal transmission strength and ground small signal reception ability, effectively improving the transmission depth of DREMWD. At the same time, a dynamic azimuth gamma measurement sub is developed for use together to achieve reservoir boundary discrimination and fast uploading, making DREMWD more advantageous in horizontal well geological steering operations. Field application indicates that the downhole high-power generator for improved DREMWD works stably, meeting the requirements for the emission intensity of electromagnetic signals and the power supply of the system. In the process of aerated drilling, it can effectively transmit downhole information. In coal bed methane horizontal wells, the transmission depth is close to 3000 m, and the geologically guided reservoir encounter rate exceeds 95%.