Abstract: A scanning electron beam brazing (SEBB) system was developed based on virtual instruments.By means of the SEBB system,experiments of the structure of four capillary tubes to a plate were carried out with a four-leaf scanning track and PID control method of heating-up velocity.The quality of brazing joints met the technical specification of structure when the highest temperature of joints during SEBB was 1050℃.Under these circumstances,the average heating-up velocity of brazing joints was 25℃/s,the holding time at the high temperature was 10s,the temperature control precision was ±1℃,and the defects such as erosion,penetration or clogging of thin wall tubes could be avoided.