This paper studied the effect of residual stress on the reheat cracking susceptibility of Super304H austenitic stainless steel weld metal using the pre-compressed CT specimen method. The plastic strain and dislocation density distribution of weld metal under different residual stresses were analyzed by ABAQUS simulation combined with EBSD characterization. The effect of residual stress on the reheat cracking susceptibility is explained from the aspect of stress-induced precipitation. The results show that CT specimens with high pre-compression force have higher residual stress and are more likely to generate cracks. As the residual stress increases, the tensile strength of the tensile specimen decreases gradually. The high residual stress region of the CT specimen closed to the U-shaped notch root has higher dislocation density and subgrain, promoting the precipitation of the small intragranuar phase, which makes the intragranular hardening more serious, and reheat cracking are easier to occur.