Abstract: With the surge in global space activities, the problem of space debris has become increasingly severe, posing a serious threat to on-orbit spacecraft and making active debris removal (ADR) missions urgent. To address the large-scale, multi-target, multi-constraint ADR mission planning problem, this paper proposes an orbit segmentation-and-patching planning method. The method decomposes the complex long-duration, multi-maneuver, multi-spacecraft trajectory optimization problem into two main stages: generating databases of short-duration trajectory segments and patching feasible segments. First, the 24-hour mission duration is divided into four overlapping time windows. Within each window, a large-scale grid search of initial orbital elements is performed to create a database of short-duration trajectory segments that can efficiently remove multiple pieces of debris. Then, a combinatorial optimization algorithm is used to select four optimal segments from the databases for each spacecraft. These segments are then patched using two-impulse transfers to construct a complete six-impulse mission trajectory. This method was successfully applied to the “Space Orbit Design” problem in the 15th National Zhou Peiyuan Mechanics Competition, where the proposed solution for three spacecraft cleared 125 pieces of debris and won the championship. The results demonstrate that this method provides an effective technical approach for large-scale ADR mission planning by transforming a complex optimization problem into a constructive process of feasible steps.