Infrared heating is featured with a high heating rate up to 50oC/s. It is a very powerful tool applied in brazing application, so infrared heating has been used to study the kinetics of brazing process in recent years. The importance of brazing Ti alloys has been increased in past twenty years due to the strong demand from chemical and aerospace industry. Based on the previous studies, the use of Ti-based brazes alloyed with Cu and Ni contents is considered as one of the best alloys in brazing Ti and its alloys due to their high bonding strength. However, the presence of Ti-Cu-Ni intermetallics in the brazed joint has a strong effect on the joint strength, and the reaction kinetics of the joint is still unclear. The purpose of this investigation is concentrated on transmission electron microscopy (TEM) study of the infrared brazed CP-Ti using Ti-15Cu-15Ni filler, and microstructural evolution of the infrared brazed joint is unveiled. It is helpful for industrial applications of Ti-based alloys.