Abstract: Towards the standardized procedure and requirement for rating the percent of shear area,i.e.pSA of DWTT specimens from pipeline steels,the machine vision technology and its application in the measurement and analysis from fractorgraphy image were introduced.The definition of valid measuring area for rating pSA,imaging system with large field of vision,large focus depth and high resolution,and suitable image analyzing and treatment algorithm as Gabor filter-cluster analysis are crucially relevant to the high quality of machine vision for rating pSA.The practical application results show that rating of pSA index could be performed more efficiently and reproducibly with the help of automatic measurement on images by machine vision technology.