Abstract: Liu Yuxi was an important poet of the mid-Tang dynasty and his seven-character and seven-word poetry has always been highly regarded. However, contemporary scholars have always focused on his seven-word poetry and paid less attention to his seven-character poetry, failing to reveal Liu Yuxi's achievements and paradigmatic significance in writing seven-character poetry. Liu Yuxi's 184 surviving seven-character poems, which are mainly about singing and answering, giving gifts, bidding farewell, and praising. This shows that Liu Yuxi has a strong ability to grasp the system, not only good at using his talents according to the requirements of specific types of systems but also flexible in handling content and structure according to his writing intentions and objects, breaking through the constraints of traditional norms and creating new norms.