Abstract: Since the beginning of the 21st century, the number of electricity users has experienced explosive growth. It is common for multiple power users to be connected to the same base tower, frequently leading to overheating accidents caused by increased resistance at line connection points. There is an urgent need for temperature monitoring and fault inspection at these connection points to enhance the safety, reliability, and stability of overhead line operation. To address this, a visual high-temperature early-warning connection device is proposed. Firstly, the research progress, development status, and existing problems of overhead line high-temperature early-warning devices are introduced. Secondly, the visual connection device is designed, utilizing the change in the elastic modulus of the memory spring during the heating process to establish a three-level high-temperature early-warning mode. Case test results demonstrate that this visual connection device can reduce the labor intensity of operation and maintenance personnel, decrease fault outage time by more than 10%, achieve a power supply reliability rate exceeding 99.6%, and possess both economic and social benefits.