Bamboo slips unearthed in recent years also have the word "Great Wall", which is earlier than the period when Qiang Zhong lived. In July 2008, Tsinghua University collected a number of bamboo slips of the Warring States Period, including a few broken ones, totaling about 2,500 pieces. Carbon 14 determines that these bamboo slips are cultural relics in the middle and late Warring States period.

The latest research achievement of Tsinghua University, Huaqing Bamboo Slips "The Year of the Department", reveals the records about the Great Wall of Qi, and provides important new historical materials for understanding the construction time of the Great Wall of Qi. In the Bamboo Slips of the Warring States Period in Tsinghua University compiled by the Research and Protection Center of Unearthed Documents in Tsinghua University, the twentieth chapter records the construction of the Great Wall of Qi: "The Duke of Jin was established for ten years and five years, and he conquered Wu from Jin to Wu. How to begin to understand the road of Wu Jin, the two countries are good, and the Duke of Lian Jin is also sad.