Abstract: Discussed in this paper is a fast algorithm to localize 3D object from an intensity image in all six degrees of freedom. The feature points distributed on the 3D model surface of an object are detected to create a feature-outline model for fast alignment between the 3D model and its real intensity image. The localization algorithm involves detecting feature points in a real image, creating feature-outline from the feature points, searching for candidates in the feature-outline model, verifying the candidates by matching corresponding feature points, and refining localization with least-squared algorithm. The experiment results show that the localization algorithm can localizes 3D object from intensity image fast and precisely when occlusion is not very serious.