Abstract: This article studied on the track long wave irregularity laser detector for the work sections of maintenance of way depot in Hohhot Railway Administration. As the detector operated, the detected data were read by hand to locate the laser spot projected on the laser target surface, it was difficult to ensure the accuracy of the data. Moreover, when reading the data, the bright laser spot would do some harm to the human eye. In this article, an industrial camera was used to collect the laser spot images on the laser target surface. Using the image processing technology, the collected spot image was processed logically and the contour was extracted. Ellipse fitting of the spot image was processed by ellipse fitting algorithm. The central coordinate of the ellipse parameter was extracted, which was the coordinates of the detected laser spot center. This method could be used instead of manual reading. Thus, the error caused by manual reading of coordinate data was reduced, and the harm of the highlight spot to the human eye was reduced.