Abstract: In the welding of high thickness structural parts,narrow gap welding technology has the advantages of high production efficiency,good mechanical properties of joints and so on. However,narrow gap welding technology is very sensitive to groove deformation,and small deformation makes a great impact on the welding process,and directly lead to the reduction of precision of structural and mechanical properties of weldments.It is necessary to deeply study the rule and control mechanism of narrow gap welding deformation. The research status of the two methods of numerical simulation and experimental measurement for narrow gap welding deformation was reviewed. Thermal-elastic-plastic finite element method and inherent strain method were mainly introduced in the numerical simulation method. Deformation punctuation measurement,displacement sensor,laser tracker and 3D scanning measurement were mainly introduced in the experimental measurement method. By analyzing the principle and characteristics of the research methods of narrow gap welding deformation,the results show that the research method combining numerical simulation with experimental measurement can reveal the rules and mechanisms of narrow gap welding deformation more accurately.