Turbine blades constitute the core energy conversion elements in hydraulic machinery systems. Among these, National Advisory Committee for Aeronautics (NACA) airfoil blades have been widely adopted due to their optimized aerodynamic performance. This study proposes a reverse engineering methodology for hydropower turbine blades based on NACA design equations, which numerically encode design intent. The workflow initiates by extracting coordinates at nine equidistant chordwise points from the airfoil design equations. Using the Least Squares Method, parameters of the camber and thickness distribution functions are solved to derive the NACA designation and reconstruct the complete profile. The final 3D blade model is generated through lofting operations. The feasibility of the methodology is validated by comparing the mean squared errors induced by codification changes against deviations in the scanned profiles. This approach effectively mitigates the impact of measurement errors through uniform coordinate sampling and demonstrates broad applicability across diverse airfoil types. The reconstructed models strictly adhere to original design principles, thereby establishing a novel, equation-driven solution for three-dimensional reconstruction of hydraulic turbine blades.