The first lady was originated in the United States, but in recent years the governments of every country have increased the attention to the first lady. Although the first lady is not an official position, the role in the diplomatic field is irreplaceable, and the first lady will continue to play a more important role in the diplomatic field. Due to various factors, the roles of the first lady in the Eastern and Western diplomatic field are different, but the position of the first lady of the East and West in the diplomatic field is very important. In addition, the first lady diplomacy is an important part of public diplomacy, to a certain extent, and it could enhance the country’s soft power and show the image of the country. The first lady uses her charm, intelligence and affinity to shorten the distance between people of the two countries, and has the ability to improve the bilateral relations. Meanwhile, the first lady as a woman has the characteristics of female which can ease the tension of the diplomatic atmosphere in foreign relations and provide a good environment for the two countries to reach a foreign target. This thesis begins from the definition of the first lady, and expounds the first lady and the first lady diplomacy. At the same time, the thesis classifies the first lady into two styles, and makes typical case analysis for each style of first ladies in order to have a more comprehensive and profound understanding of the first lady and the first lady diplomacy through the analysis. Although, due to a variety of economic, IV political, cultural and other reasons, there are still some obstacles to fully implement the first lady diplomacy in the present, in the future the first lady diplomacy will give full play to the unique role in the diplomatic field, and the first lady system will also go farther in the future.