For joints showing high shear strength value of more than 160-202 ㎫ at room temperature, fracture mode and strength distribution were investigated after the introduction of thermal shock by water-quenching at 893K. Average shear strength of thermally-shocked Si₃N₄/304 joints were 64.7, 86.6 and 75.1 ㎫ respectively for Cu-Ag-Ti, Cu-Ag-Ti-Mo and Cu-Ag-Ti-Al alloy. Factor dominated the fracture mode and the strength distribution of thermally-shocked Si₃N₄/304 joints was four types of defects introduced by water-quenching. Predominant factors of these defects were maximum tensile component of residual stress formed into the Si₃N₄ ceramic under the reaction layer interface and cracks formed at the interface between 1`st(Ti_5Si₄/Ti_5Si₃) and 2`nd reaction layer(FeTiSi).