This study investigates the long-term impact of the Great Wall established in the Ming-dynasty on corporate tax avoidance. The centralized administrative system in the borderlands on the south side of the Great Wall shaped a formal unified legal environment, while "feudal lordship" system had an obvious influence on the north side, which enables us to examine the legacy impact on firms with a regression discontinuity design. We find significant lower tax avoidance by firms in the region south of the Great Wall relative to firms on the north of it, and this difference is pronounced for non-SOEs.