By the methods of finite element analysis (FEA), the temperature distribution of thick plate narrow gap submerged arc welding (SAW) is analyzed. Also the residual stress distribution of upper surface, lower surface and along the thick direction is presented. The temperature distribution of specific points is measured by the temperature measurement system of thermocouple. After welding and cooling for a long time, the residual stress of the specific points of the upper and lower surface of the plate. The testing results are coincided with those of FEA which proves the rationality of this finite element model and offers reference to appraise the weld performance. In particular, the residual stress distributing curve in the thick direction which is inconvenient to measure is gained by FEA. There is large deviation between these two results in the base metal zone and the reason of this deviation is presented.