Advanced High Strength Steels (AHSS) represent an important technology in efforts to lightweight vehicles for improved fuel-efficiency and occupant safety. Main difference between AHSS and conventional high strength steels is their microstructures. Conventional steels are single phase materials whereas AHSS are primarily multiphase materials having several different phases in it, depending on its chemical composition and heating process. For this reason, the microstructure-based modeling methods have been usually adopted for study of AHSS. It is well known that, along with the microstructure itself, the constituent phase properties (i.e., stress-strain curves) also play a crucial role in the microstructure-based modeling. Therefore, it is important to accurately measure/estimate the phase properties of constituent phases of AHSS. Various methods may be adopted to estimate the phase properties of AHSS, such as in-situ high energy X-ray diffraction (HEXRD) test, nano-pillar compression test, nano-indentation test. In this study, two test methods, in-situ HEXRD and nano-indentation, are compared in estimating the constituent phase properties for the purpose of microstructure-based modeling work. For this purpose, actual microstructure-based model is first generated based on the information from electron backscatter diffraction (EBSD), scanning electron microscopy (SEM) of a quenching & partitioning (Q&P) steel. The constituent phase properties are then estimated from HEXRD and nano-indentation tests and subsequently used in the model. From the comparison of modeling results based on the phase properties of the two tests, the relative performance of the two test methods will be discussed and then the applicability of nano-indentation test in the microstructure-based modeling method will be evaluated.