Abstract: Commonly, surface/surface intersection algorithm is used repeatedly to solve the intersection problem of a pair of moving surfaces. When both surfaces are moving along a straight line, coherence exists in the successive sets of intersection curves, this fact can be utilized to accelerate the process of solution. This paper proposes an optimized approach based on topology similarity. First, it pre-processes surfaces to achieve topology transition points (TTP) which indicate the topological features of intersection loops. According to TTP graph, the initial point searching strategy and intersect curve topology can be fixed, and then all of the intersection loops can be calculated by tracing algorithm. The algorithm can handle degenerate cases such as loop vanishing and singularity point vanishing, calculating the intersection loops robustly and effectively.