The tenon tooth serves as a vital component of aero-engine blades, where its profile dimension precision plays a pivotal role in establishing the firmness of blade installation and ensuring the safety of engine operations. However, the conventional manual projection continues to be employed as the prevailing measurement approach in current industrial production, exhibiting drawbacks including low efficiency and inconsistent accuracy. Drawing upon machine vision technology, this paper puts forth a novel measurement method and designs a corresponding system aimed at measuring the dimension of aero-engine blade tenon tooth profiles. Employ an industrial camera to acquire realtime images of tenon tooth profiles. The obtained images are subsequently processed using machine vision software based on HALCON, which includes sequential operations such as image pre-processing, edge extraction, geometric feature extraction, and geometric dimension transformation. Through these operations, precise dimensional information of the tenon tooth profile is obtained. Additionally, a visual graphical software with interactive information is designed using Visual Studio 2019 to facilitate the analysis and visualization of the obtained data. The experimental results demonstrate that the developed system achieves an average accuracy error of 0.023 6 mm and 0.270 1° for straight line and angle measurements, respectively, and the time consumption for a single measurement does not exceed 2 s. Compared to the conventional manual projection measurement method, the developed system significantly enhances the accuracy and speed of measurements while reducing manual labor costs. Furthermore, it exhibits the promising potential for user-friendly on-site deployment, offering enhanced convenience in practical applications.