By analyzing the case documents of judicial bamboo slips from Baoshan Chu Tomb, this paper finds that in the Warring States Period, there were practices of judicial proceedings similar to the “direct appealing system” in the State of Chu, which were well developed and reached a systematic level. The “direct appealing” system in the State of Chu might be the practical origin of the system of “striking the stone or drum to tell grievance” in the Rites of Zhou, a book compiled in the same period. Therefore, the direct appealing system took shape in the Warring States Period. So we have to rectify and re-examine the conventional idea that the direct appealing system didn’t form until the Han and Tang Dynasties.