Abstract: This paper systematically reviews the current development status and future trends of temperature detection technologies for overhead transmission lines, focusing on the principles, application scenarios, and performance of contact methods (optical fiber sensing, surface acoustic wave sensors) and non-contact methods (infrared thermography). Engineering practices, such as the "Sea Breeze + Salt Fog" monitoring system in Zhejiang and the "Beidou + Optical Fiber" technology in Sichuan, verify the effectiveness of online temperature monitoring in improving operation and maintenance efficiency. The study indicates that optical fiber sensing (DTS/FBG) is suitable for long-distance conductor temperature monitoring due to its strong immunity to electromagnetic interference, distributed measurement capability, and long service life; Surface acoustic wave (SAW) and thermistor technologies, featuring passive wireless operation or low cost, are widely applied to critical joint monitoring; Infrared thermography is significantly affected by environmental conditions and mainly serves as an auxiliary inspection tool. Future research and applications will focus on improving measurement accuracy, reducing costs, enhancing multi-source data fusion (e.g., integrating temperature, meteorological, and load data), and supporting dynamic line rating. The deep integration of temperature data with intelligent algorithms will provide systematic solutions for transmission line condition assessment, lifespan prediction, and maintenance strategy optimization.