Abstract: Since the inception of biological metrology discussions in the mid-1990s, scientists have focused on developing biomolecular reference methods to achieve precise, reproducible, and SI-traceable results. Over the past two decades, protein metrology has seen significant progress in purity and content measurement methodologies. However, structural and activity measurements remain exploratory without clear guidelines. As protein function relies on its higher-order structure, the development of thermal stability assessment techniques has emerged as a critical research focus. This review summarizes three mainstream protein thermal stability measurement technologies: Differential Scanning Calorimetry (DSC) directly measures heat absorption during protein denaturation to provide thermodynamic parameters, Differential Scanning Fluorimetry (DSF) monitors stability through intrinsic protein fluorescence or extrinsic dye-binding fluorescence signals, and Circular Dichroism (CD) tracks dynamic changes in secondary structure via far-ultraviolet spectral peaks to assess conformational stability. These methods are widely applied in biopharmaceuticals, industrial enzyme design, and biomaterial development. Comprehensive analysis reveals that no single technique can fully characterize the complex stability of proteins. Future advancements in protein thermal stability metrology will rely on technical standardization, multi-method integration, and the development of hybrid approaches to enhance accuracy and applicability.