Abstract: "Picking up a Willow Branch" is a cultural custom in ancient China. The Custom can be dated back to Han Dynasty, and seen in the departure poems os Sui, Tang and later Dynasties. This article discusses the evolutional process of "Picking up a Willow Branch" and the famous singing verse "Picking up a Willow Branch". "Picking up a Willow Branch" in poems did not have any connection with departure before Sui and Tang Dynasties. Only in Sui and Tang Dynasties did "Picking up a Willow Branch" become a special descriptive phrase for the departure. The connection of "Picking up a Willow Branch" with departure went throuhg a long process of separation and relation, whose relevant juncture was at the Xiao-Liang stage in the Nan Dynasty. "Picking up a Willow Branch" functioned as symbols of departure emotion and longing for a friend far away, connoting "a smooth journey" and "peace and well-being" in its cultural sense, and the action itself is driven by the religious emotion.