Austenitic stainless steels are promising engineering materials demonstrating good corrosion resistance and good formability but they have also relative low yield strength. Among the different strengthening mechanisms, transformation induced plasticity is one of method to improve strength. Metastable austenitic stainless steels undergo a straininduced martensitic transformation, where the metastable austenite phase is transformed to the thermodynamically more stable ??-martensite phase due to the plastic deformation. Transformation induced plasticity (TRIP) can increase the ductility of material during deformation process and delay the necking and cracking of material because the retained austenite transfers into martensite. Mechanical properties of austenitic stainless steels are highly dependent on the martensitic transformation, predicting the amount of martensite phase to determine the mechanical properties of the material is very important. In this study this transformation is modelled in 201 austenitic stainless steel through tensile and rolling tests. The Olsen- Cohen model is used to predict the martensite volume fraction through tensile and rolling tests. The constitutive model is implemented into ABAQUS/UMAT to analyze the martensite volume fraction through tensile test, and this model is implemented into ABAQUS/VUMAT to analyze the martensite volume fraction through rolling test. The experimental measurements with using Ferritescopy was performed. The martensitic volume fraction tested by Ferritescopy in comparison between experiment data and simulation were agreeable.