In the process of drilling and developing unconventional oil and gas resources with complex formation structure, the contact area between wellbore and reservoir can be maximized only by keeping the wellbore trajectory running through the reservoir. Every foot of drilling out the reservoir represents the loss of oil and gas production. The measuring point of geological parameters of traditional geosteering technology is far from the drill bit, which leads to the time lag for the ground geosteering engineer to make the decision of trajectory adjustment, especially when drilling in thin reservoirs, the reservoir boundary is often drilled. Therefore, it is necessary to develop a geosteering system with near-bit imaging function. The near-bit imaging geosteering instrument developed in this paper has a geological parameter measuring sensor directly connected to the bit, which can measure the real geological information of the formation near the bit at the first time when the formation is opened, and at the same time image the trajectory of the drilled hole 360°. By using the wireless short-distance communication function of low-frequency electromagnetic waves, the dynamic well deviation and azimuth gamma information measured at the drill bit are wirelessly sent to the MWD system above the screw drilling tool, and then transmitted to the geological steering engineer on the ground by the MWD system as the decision-making basis for adjusting the well trajectory. The field drilling test shows that the system can maximize the contact area between the wellbore and the reservoir by optimizing and adjusting the wellbore trajectory, and can calculate the formation dip angle according to the dynamic borehole deviation measurement data to determine the spatial position of the wellbore trajectory in the reservoir. After the near-bit measurement information is transmitted to the ground in real time through MWD system, the geological steering engineer can adjust the drilling direction in real time to avoid drilling out the reservoir and effectively improve the drilling rate. The gamma imaging while drilling system with direct connection of drill bit provides a fast, accurate and real-time formation evaluation method. Further improving the technical level of drilling and completion of horizontal wells with reservoir gas is a very important technical support for reducing costs, improving the rate of drilling and completion of reservoirs, improving the quality of drilling and completion of horizontal wells and reducing complex accidents in the future.