It is of great significance to fast weld and repair damaged parts in electroless and gasless field. So, based on Selfpropagating High-temperature Synthesis (SHS), this paper investigates the SHS brazing of thermit reaction. It is found that the heat obtained by SHS thermit reaction can not melt the base metal, however the silver solder with the melting temperature of 595°C to 605°C can all just melt in the middle of the base metal to achieve SHS brazing. In the experiment, as the surface tension, the molten solder is more likely to wet the slag which is with a larger surface tension, resulting in the poor wettability between solder and base metal. By adding a certain amount of silver brazing flux into the powder can solve the problem of base metal wetting. When the silver brazing flux and the powder are in a ratio of 10:1, solder melt completely, and can be separated with slag, there is a good weld surface. With the increase of silver brazing flux, the slag is more loose and easy to removal. The solder and base metal coating is better. However, with further increase in silver brazing flux, the heat from the reaction reduces, solder can not melt. And with the increase of the powder, the slag and the solder can not be separated. SHS brazing combines the thermit reaction heat with the brazing technology to achieve the low carbon steel welding. Using the heat of thermit reaction to melt the solder then weld the steel can overcome the defects of poor quality of traditional welding which use the reaction products. And the operation is simple. SHS brazing achieve the emergency equipment welding under the condition of no electricity, no gas and equipment.© (2010) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.