Abstract: In view of problem that core temperature of cable joint cannot be measured directly, the paper applied finite element method to establish a model of steady temperature field distribution of cable joint, used ANSYS software to simulate and analyze the temperature field distribution, obtained the relationship between the core temperature and surface temperature of the cable joint. It proposed a design scheme of temperature monitoring system for cable joint based on temperature field according to simulation result, gave design of power supply and data processing of the system, so as to provide a theoretical basis for monitoring of joint temperature and running status of cable in engineering.