Processing of super long inner hole of large parts is more and more common, the processing requirements are also getting higher and higher. Trepanning processing for large diameter and super long inner hole was researched.Based on analyzing technical difficulties of typical super long hole, a method of efficient trepanning processing was put forward, focusing on technological measures and process monitoring strategy. The actual product verified the reliability of the machining strategy.The processing strategy provides idea and experience for process preparation and realization of similar special product, it has a practical significance.