The approximate accuracy of the micro-macro decoupling analysis method is studied with a view to its application to predicting detailed micro-and macroscopic responses of polycrystalline metals subjected to plastic forming. A simple example problem assuming three dimensional cold-forming is set up for examining the micro-and macroscopic analysis results in comparison with the micro-macro simultaneous coupling analysis method. The qualitative reproducibility in both the micro-and macroscopic deformation states as well as the corresponding stress states is confirmed. And even the quantitative accuracy is obtained for the plastic-deformation-dominant forming process to some extent. It is also pointed that the accuracy in the responses especially during unloading process after the forming tends to depend on the employed macroscopic homogenized constitutive equation in the decoupling method.