Within the Tongbai complex contains a typical rock unit called L tectonites, which is tectonically located within the core of the Tongbai orogenic belt and bounded by two symmetrical ductile shear zones (sinistral zone in the north and dextral zone in the south). Because of the special tectonic position of L tectonites, which is located in the intersection parts of shear zones, Tongbai antiform, Tongbai doom and so on, the formation mechanism of the L tectonites can be provide an important constraints on better understanding the evolution of Tongbai orogenic belt. By the study of structural mechanism and deformation conditions of L tectonites, and along with previous research results of other main tectonic units in the Tongbai Mountain, it can be suggested that the formation process of L tectonites in Tongbai was mainly controlled by the two ductile shear zones in the north and south sides of the Tongbai complex. Before Cretaceous, Tongbai complex rock unit underwent near EW trending pipy ductile shearing with the ductile shear zones, resulting in the formation of a set of typical L tectonites. The formation of L tectonites indicates the Tongbai orogenic belt might go through an eastward pipy ductile shearing of the middle and lower crust material, followed by a large scale magmtic ascending and increasing buoyancy of L tectonites in the core of Tongbai Mountain in late Cretaceous. The L tectonites ascended with the shear zones but the main feature has not been transformed and presents today's geometry characteristics with uneven uplifting of the Tongbai Mountain. The L tectonites might reflect that pipy shearing gave rise to the main structural characteristics of Tongbai orogenic belt with a nearly east west linear structure style.