It has been widely accepted that the Tan- Lu fault zone originated during the convergence of the North China Craton and Yangtze Plate. Origination of the fault zone deals with the convergence mode of the two continental plates. However, this important issue remains controversial for a long time. On the basis of structural and geochronological results from the Tan- Lu fault zone and surrounding foreland regions, origination of the fault zone is analyzed comprehensively in this paper. Origination structures remained within the fault zone are sinistral ductile shear zones, and muscovite 40Ar/39Ar ages from the shear zones range from 239 Ma to 217 Ma. The Xu- Huai arcuate thrust- nappes in the margin of the North China Craton and the arcuate fold belts around Jiujiang in the Yangtze Plate result from the point collision at the Sulu and Dabie orogens respectively. The margin of the North China Craton to the west of the fault zone shows a feature of rigid continental block during the convergence without large- scale dragging and bending phenomena. In contrast, foreland structures of the Yangtze Plate to the east of the fault zone display large- scale dragging and bending phenomena related to the convergence. A mid- crustal ductile décollement zone of the Yangtze plate is exposed in the northern Zhangbaling uplift belt to the east of the Tan- Lu fault zone. It gives muscovite 40Ar/39Ar ages of 245~218 Ma, and shows kinematics controlled by sinistral motion along the fault zone. The structural and geochronological information suggests that the Tan- Lu fault zone originated during the convergence of the North China Craton and Yangtze Plate, and represents an oblique convergent boundary of the two continents. The activity time of the origination is synchronous with the continental subduction in the Dabie and Sulu orogens. The North China Craton had a southward promontory (indenter) in front of the Dabie Orogen originally, resulting in indentation during the collision and the oblique convergence along the indenter boundary (initial Tan- Lu fault zone). The convergence accords with the indentation- induced slab tearing model proposed previously.