Abstract: The computation of curve-curve intersection is aproblem important issue in computer aided geometric design.However,the existing curve-curve intersection algorithms cannot deal with the coincident curves.Based on the coincident conditions of two cubic Bézier curves,in this paper a new algorithm presented to judge whether two cubic B-spline curves are coincident.For each B-spline curve,the algorithm first subdivides it into Bézier segments,and then determines whether two Bézier segments can be merged.By merging the adjacent or overlapping Bézier segments,the problem is converted into the coincident judgment of two sets of cubic Bézier curves.The correctness of the proposed algorithm is proved in this paper.Several experimental results demonstrate the effectiveness of the proposed algorithm.