Note is the most commonly used form of document in modern foreign exchanges. The American National Archives Collection of Consular Reports of the Modern American Consulate in Mukden contains notes on the exchanges between the modern United States and Northeast China. These notes are rich in content, both in Chinese and English, and are well preserved. They carry rich and diverse historical connotations in the form of diplomatic documents, so they have high archival value. This paper carefully combs the consular note archives, and carefully classifies them from the perspectives of direction, language, cause, and parties involved, and then conducts in-depth research on the style and historical connotation of the documents. This research will help archival science and history better understand the evolution of the form and content of modern note documents and the deep historical pulse it contains. The development of the form and content of the note has become the epitome of the modernization of Sino foreign exchanges. The Sino-U.S. note of exchange has gradually evolved from a traditional complicated formula to an efficient and sophisticated style, which has also become an example of the mutual blend and influence of Sino-U.S. diplomatic instruments and concepts.