Abstract: The fracture morphology of cold crack in the implant of HSLA steels produced in China has been investigated with SEM and the fractographic features are discussed.The observed results show that the main factors which modify the fracture features are the chemical composition of welded materials,the diffused hydrogen in deposited metal and the applied stress.When the Pcm of base metal and the diffused hydrogen H in deposited metal are increased or the applied stress goes down,the intergranular fracture region on fracture surface extends,and a dimple rupture region will be formed if on the contrary.Finally,to sum up the influence of various factors and to generalize the regularities of fractographic appearances,the fractographic features of the experimental steels are schematized.Thus some hints for the prevention of cold cracking could be obtained.