Abstract: Rail thermite welding technology is the key technology to realize wide area smoothness of seamless circuit. In this paper, damage modes and mechanisms of rail thermite joints, such as residual stress, non-metallic inclusion solid particles and residual gas are summarized. Based on this, process control of thermite welding technology and regulation mechanisms of exploration and application of new materials and new devices to improve strengthen and performance of weak area of joints are summarized. In addition, technical methods for detecting thermite welded joints and service performance are further described. Finally, development of rail thermite welding is discussed and prospected. The results show that formation mechanism of residual stress, residual gas and non-metallic inclusion is different. Residual stress is mainly caused by the difference of thermal expansion coefficient, elastic modulus and temperature coefficient between base metal and flux powder. Residual gas is captured by molten pool before solidification due to superposition effect of surface tension effect, convection effect and reverse stamping effect. Formation of non-metallic inclusions is mainly related to insufficient metallurgical reaction, insufficient filling of molten metal and poor fluidity of metallurgical products. Methods of process control and computer simulation control are different. Process control is mainly through effective heat treatment process and hybrid welding technology to control service performance of the joints. Computer simulation control is mainly to realize quantification and graphics of multi-physical field distribution and action mechanism of thermite welding reaction. For detection and service performance evaluation technology of thermite welded joints, non-destructive testing, image processing, machine learning, laser measurement and other technologies are currently used to achieve detection of shape and position parameters, structural characteristics, service performance, life cycle and health status of thermite welded joints. In the future, based on further research on dynamics, energy state changes, defect formation and development mechanism and law of thermite welding pool under the action of multi-principal elements, optimization and innovation of thermite welding technology from multiple angles and multi-dimesions can be realized from aspects of component purification, in-situ control, complex parameter response, multi-physical field superposition, multi-mode technology fusion, and scientific norms and standards.