Abstract: Horizontal well geosteering technology is a core means to enhance the drilling encounter rate of oil and gas reservoirs. With the continuous advancement of unconventional oil and gas exploration and development, complex geological conditions have raised higher demands on the precision and adaptability of this technology. This study clarifies the challenges of geosteering for unconventional oil and gas horizontal wells by reviewing the processes and key technologies of horizontal well geosteering, and expounds on the research progress and application prospects of this technology. The results show that horizontal well geosteering technology mainly consists of three implementation stages: geological modeling, landing and targeting, and horizontal section tracking. By relying on technologies such as real-time data acquisition during drilling, 3D geological modeling, and real-time trajectory regulation, the wellbore path is dynamically optimized, effectively enhancing the drilling encounter rate in high-quality reservoirs and the efficiency of oil and gas extraction. Currently, this technology still faces challenges such as damage to downhole instruments in high-temperature, high-pressure environments, delayed transmission of measured data, difficulty identifying sweet spots due to reservoir heterogeneity, and limited dynamic trajectory control. In recent years, the industry has gradually achieved upgrades in high-temperature drilling equipment, improvements in high-speed data transmission systems, the establishment of an integrated geological engineering collaboration platform, innovative high-precision 3D reservoir modeling methods, the formation of differentiated guidance schemes for multiple types of reservoirs, and significant application results in intelligent collaborative construction modes. In the future, geosteering technology will steadily develop towards intelligence, real-time capabilities, and refinement. It will rely on big data and digital twin technologies to build an intelligent closed-loop regulatory system, accelerate the localization of research and development for core equipment, expand cross-industry application areas, and balance efficient oil and gas exploration and development with green and low-carbon development concepts. The aforementioned research results provide important references and lessons for the in-depth application of horizontal well geosteering technology in unconventional oil and gas exploration and development.