Abstract: The Yihe-Suhe fault belt is a Mesozoic rift structure, consisting of many secondary faults. The left lateral strike-slip motion along these faults between the Jurassic and the Cretaceous periods appears to be the initial stage of development of the rift. Then a florishing stage of faulting depression and extension was in Cretaceous time. Since the Tertiary period it had become a compressonal tectonic belt characterized by the intensive folding and thrusting, and the rift is disappeared.