Abstract: A measurement method of typical geometric parameters of flow guide devices was analyzed. The measurement mathematical model was established. The detection algorithms for key geometric parameters—coaxiality, installation angle of the vanes, and back angle of the vanes—are theoretically derived. These algorithms enable the use of simple linear displacement sensors to achieve the measurement of complex geometric parameters of the flow guide device. Additionally, a validation platform was developed to verify the proposed algorithms. Validation data demonstrated that the measured values from the platform closely align with the true values, indicating excellent repeatability and minimal bias in the algorithm. This method facilitates automated measurement of geometric parameters for such flow guide devices, meeting the requirements for automation in production line inspection processes.