Abstract: According to exist issues of stereomapping in sharp undulating ground, such as mountainous area or cities, this paper proposed an approach for computing the overlap of neighbor stereomodels. Compared to traditional approaches, this approach designs aerial routes by computing the actual overlap of neighbor stereomodels instead of computing the overlap of neighbor images. The primary experiment shows that this proposed approach not only satisfies to the stereomodel overlap requirement in stereomapping, but also dramatically decreases amounts of images and aerial routes.