TRIP steels have been confirmed to have both excellent strength and ductility, however there is no model that reproduces the deformation behavior of TRIP steels with microstructure evolution of martensitic phase. In this report, we conduct a tensile loading analysis for TRIP steel polycrystalline specimens using a material model for TRIP steel coupling the order field of the multi-phase-field (MPF) model and the deformation field of the dislocation-crystal plasticity model developed in our previous report to predict numerically the unique mechanical response and microstructure formation. Furthermore, it is noted that the strength and ductility of TRIP steels can be controlled by varying the energy barrier to phase transformation.