The field cases for scratch-induced stress corrosion cracking (SISCC) of steam generator tubes in PWR and current studies in laboratories were introduced.According to analysis result of broke tubes, scratches caused intergranular stress corrosion cracking (IGSCC) with outburst.The effect of microstructure for nickel-base alloys, residual stresses caused by scratching process and water chemistry on SISCC and possible mechanism of SISCC are discussed.The result shows that scratch-induced microstructure evolution contributes to SISCC significantly.The causes of scratches during steam generator tubing manufacturing and installation process are stated and improved reliability with scratch control is highlighted for steam generator tubes in newly built nuclear power plants.