Abstract: The influence of hot rolling process on the microstructure and residual stress of 304 stainless steel welds was investigated using a rolling vacuum composite plate, with rolling reduction ratios set at 0%, 10%, 20%, 30%, and 30%/20%. The results show that, as the rolling reduction ratio increases, the grain distribution becomes progressively uniform, and the average grain size diminishes from 150.3 μm to 77.9 μm; a portion of high-angle grain boundaries transforms into low-angle grain boundaries（LAGB）, with the proportion of LAGB rising from 62.0% to 89.6%; these LAGB impede dislocation movement, causing dislocations to accumulate at the LAGB, and the density of geometrically necessary dislocations increases from 1.32×10¹³m^-2to 3.61×10¹³m^-2; the increased dislocation density leads to greater lattice distortion within the material,altering its internal stress state, resulting a stress transition from residual tensile stress of 23.7 MPa to residual compressive stress of 114.3 MPa.