Abstract: The Dashibei Fault in the Hushan region, Nanjing is located in northwest flank of the Dashibei syncline and exhibits as
normal fault in section. Based on the analysis of structural elements, including the faults and joints, and the study of tectonic stress
field in study region, together with field observation, we propose that the Dashibei Fault mainly present as right-lateral strike slip with
some degree of normal fault. The NE folds (Ningzhen mountain range), NW right strike-slip faults and NNW sinistral strike-slip faults
were formed due to the NW-SE tectonic stress during in the Indosinian. The NW right strike-slip fault displays false appearance of
normal fault in NE cross section，and thus as a typical teaching case of fault effect.

Key words: Dashibei fault, right strike-slip faults, fault effect, Hushan Hill of Nanjing