Abstract: The vacuum interrupter is a core component of the vacuum circuit breaker, and the coaxiality of its conducting rod is crucial for the normal operation of the equipment. However, the current indirect detection methods based on sensors have limitations in detection accuracy, complex data processing, and incomplete coverage of fault types, making it difficult to reflect the true state of the equipment in realtime and accurately. This paper proposes a fault diagnosis method for the coaxiality of the vacuum interrupter's conducting rod based on X-ray imaging. By using a directional template matching algorithm,multiple images from different positions are stitched together to form a complete DR image of the vacuum interrupter. Leveraging the axisymmetric structural characteristics of the conducting rod, a cross-correlation algorithm is designed to determine the center position of the rod. The rod image is divided into multiple segments along the vertical direction, with the center point of each segment calculated and the optimal symmetry axis of the rod determined by least squares fitting of these center points. Experimental verification shows that this method can effectively detect the tilt fault of the conducting rod. In the experiment,six sets of faulty data and one set of normal data were used. The slope differences corresponding to the faulty data were 0.081, 0.169, 0.081, 0.068, 0.224, and 0.126, respectively, while the slope difference for the normal data without tilt was 0.005. According to the experience set, the guide bar tilt slope difference threshold is 0.02; the above data are consistent with the diagnostic conditions of the fault, to verify the method's effectiveness.