Abstract: The temperature and stress field of laser full-penetration welding process for 16 mm-thick stainless steel plates were numerically simulated using commercial software ABAQUS, during which the heat source model was described by a combination of one volume heat source and two super-Gaussian surface sources, respectively representing the keyhole thermal conduction and plasma/metal vapor thermal radiation. Results show that the weld joint with hourglass cross section obtained by simulation agrees well with that of experiments; the longitudinal residual stress in the plate is the largest, followed by the transverse stress, and finally the transverse through-thickness stress; longitudinal tensile stress exists mainly in the zone 25 mm away from the center line of weld, and the maximum value has already exceeded the yield strength; an angular distortion of 0.35° after welding is predicted, and such small distortion could be attributed to the high and dense energy input by the laser, which can fully penetrate the plate by one pass without weld groove.