The interface structure between the Si and NiSi2 epitaxially grown on the (112) Si substrate was studied using high resolution transmission electron microscopy and computer image simulation. The results showed that the interface between Si and NiSi2 epitaxially grown on the (112) Si substrate has six different types:type A NiSi2 (111)/(111) Si, type A NiSi2 (001)/(001) Si, type B NiSi2 (111)/(111) Si, type B NiSi2 (112)/(112) Si, type B NiSi2 (221)/(001) Si, and type B NiSi2 (114)/(110) Si. And there are one or more different atomic structures for one type of interface.