To tackle the problem of complexity and time-consuming in simulating the metal 3D printing process, a modified inherent strain method is adopted to achieve accurate and rapid prediction of residual deformation in 3D printing process while taking the metal selective laser melting (SLM) processing process as the research object. Considering the periodicity of 3D printing process, thermal-elastic-plastic coupling analysis is carried out for two successive printing layers, and then the equivalent modified inherent strain load of 3D printing process is extracted based on the modified inherent strain theory. The extracted modified inherent strain is applied to the elastic finite element model layer by layer to realize efficient simulation of 3D printing process and accurate prediction of its residual deformation. At last, the accuracy and efficiency of the modified inherent strain method in predicting 3D printing residual deformation are verified by comparing the results of the thermo-solid coupling analysis and the 3D printing experiment.