Abstract: Field-assistod self-prupagated high temperature joining (FASHJ) is a new method for joining new materials. The interlayer for FASHJ was investigated. It was found that the high exothermie elements were necessary in the reaction system for FASHJ and elements with low molten temperature were applied to decrease the ignition temperature of reaction system. Based on this, the Ti-Al-C system was selected as FASHJ interlayer. The optimized content was determined as Ti5Al4C1 according to the field-assisted self-propagated high temperature synthesis reaction result of interlayer with different contents. The microstructure analysis was carried out and the TiAl and TiC were found in the interlayer reaction product.