Changfu is a part of the Ming Dynasty officials dress system，with the promulgation of the maritime prohibition policy in the early Ming Dynasty，and gradually spread to the entire East Asian cultural circle through official channels under the background of tributary system. In the “Portraits of many countries coming to diplomacy”，it shows its use as a formal official dress in diplomatic occasions under the rule of the Qing Dynasty. This paper takes Annam officials wear the Ming Dynasty Changfu as the breakthrough point，from the Wusha hat，Buzi，color and other clothing information elaborated，and in combination with related literature and material evidence，to further explore the reason and purpose of Annam’s use of Ming Dynasty Changfu in the mid to late eighteenth century from the perspective of maritime history and the Qing government’s response. The research shows that the image of Annam official Changfu mainly comes from the early Ming Dynasty style，Since the Qing Dynasty entered the Central Plains，Annam，which had been a vassal of Ming Dynasty，regarded the clothes as the old Man customs，and always respected the Han culture themselves，emphasizing its continuity with the Han nationality in the central Plains. The continued use of Ming Dynasty Changfu is a concentrated reflection of the spread of Han customs and cultural identity.