The invention discloses a contour registration method based on machine vision train guide rail contour measurement. The contour measurement comprises the following steps: S1, acquiring a steel rail image; S2, processing the acquired steel rail image by a computer to obtain a single-pixel curve of the cross section of the steel rail; S3, calibrating and restoring; S4, carrying out the contour registration, wherein the contour registration comprises the followings sub steps: S41, integrating a real contour line and a standard contour line into a coordinate system, and obtaining an angle between the real contour line and the standard contour line by utilizing an asymptotic line of the two contour lines; S42, rotating the real contour line, and enabling the asymptotic lines of the two contour lines to be parallel to each other; S53, translating the real contour line, and enabling the end point of the real contour line to be overlapped with the end point of the standard contour line. According to the registration method, the real contour line and the standard contour line are integrated into the coordinate system, the real contour line is processed, the asymptotic lines of the real contour line and the standard contour line are parallel to each other, and the end points of the two contour lines are overlapped, so that the registration result is accurate, convenience in observation and calculation can be realized, and reliable abrasion data can be obtained.