Abstract: The influnse of inhomogeneity on stress corrsion cracking (SCC) was studied, which simulate the welded joints of steel, and the roles of inhomogeneity on the stress corrosion cracking nere also discussed. The conclusions are: (1) The crack growth rate of inhomogeneous bodies which consist of 4340 steel, 16Mn steel and A3 steel decreases attribute to the inhomogeneity. (2) Tlie fractogragh of inhomogeneous bodies are of mixed fracture feature (intergranular+tear grain). The higher the stress intensity factor or the narrower the hard layer, the more tear grains are. (3) In condition the inhomogeneous bodies are MH type, crack growth will turn toward the soft region.