Abstract: A series of physical and chemical changes took place by the fault activity for Yingshan carbonate reservoir of the Lower Ordovician in Tazhong area. They are the fractures related to the faulting formed in the reservoir near the faults, a high porositypermeability zone, multistage and multi-orientation fractures that improve the carbonate reservoir quality; the fractures as channels for deep fluid migration and various modification processes like solution, metasomatosis and dolomitization; the near-surface fault activity that connected with surface water, deepened the depth of karst, solution and fracture development, thus increasing the effective reservoir spaces.

Key words: Tarim basin, Lower Ordovician, Yingshan formation, carbonate rock, fault activity