690 nickel-based welding metal has a high susceptibility to ductility dip cracking (DDC) at high temperature.Strain-to-fracture (STF) test based on Gleeble-3500 thermo-mechanical simulator was carried out to evaluate the high-temperature DDC susceptibility of domestic WNi 690 welding metal at different welding parameters and compare with the test results of the imported Inconel 152 electrodes for analysis,and the grain orientation and characteristics of grain boundary were observed in combination with SEM and EBSD.The test results show that the minimum critical strain of high-temperature DDC takes place near 1 050℃,the minimum critical strain of imported Inconel 152 is about 4%,while that of WNi 690 is about 5%.