Abstract: Micro surface topographies of four differently machined surfaces of 1Cr11Ni2W2MoV stainless steel were quantitatively characterized by atomic force microscopy,and the effects of different characteristic parameters on micro-stress concentration and different micro topographies on fatigue strength reduction were analyzed using finite element methods.It is found that the characteristic parameters may affect the micro-stress concentration obviously and it is insufficient to use a single surface roughness parameter to represent the effects of surface quality on micro-stress distribution.The difference of the fatigue resistance between different surfaces can be perfectly correlated with the surface characteristic parameters,and it is reasonable to use them to analyze the change of fatigue performance caused by different surface fabrication.