As insufficient stability and accuracy of traditional electrified railway catenary detection, a catenary automatic detection system is proposed, which has the ability to automatically identified rod numbers as the basis for catenary pole position and image index detection. Firstly, the system introduces the process of multi-frame rod number identification, and then analyzes three most common feature extraction methods,i.e.shape context(SC), corner representative shape context(CRSC) and center shape context(CSC). Finally, the CSC algorithm is chosen to be integrated into the proposed system as the most effective method of rod number recognition. Experiments show that the proposed system achieves better recognition results in terms of real-time performance and reliability than other method. Specifically, the proposed system can run smoothly at about three hundred kilometers per hour and provide a practical method to detect the position of electrified railways.