Accurate and reliable detection of core point for fingerprint classification and matching are important. This paper introduces a good method for core point detection in fingerprint to improve accuracy of the position and reliability of the core point. According to the definition of the core point is that the greatest point of curvature ridge, this paper use the ridge line tracing methods derive the core point. The experimental results show that the method can extract the core point from the fingerprint image more accurately and reliably, and has good robustness.