A method of manufacturing a ceramic/metal composite structure includes the steps of: providing a ceramic substrate; forming a metal interface layer on the ceramic substrate; placing a copper sheet on the metal interface layer; heating the ceramic substrate, the metal interface layer and the copper sheet so that the metal interface layer forms strong bonds with the ceramic substrate and the copper sheet. Multiple stages of pre-oxidizing processes are performed on the copper sheet at different temperatures and in different atmospheres with different oxygen partial pressures before the copper sheet is placed on the metal interface layer. The metal interface layer provides a wetting effect for the copper sheet to the ceramic substrate at a high temperature so that the copper sheet wets a surface of the aluminum oxide.