Korean Chinese international trade correspondence belongs to the teaching field of "Special purpose language". It takes various communicative contexts as the premise, and the communicative context is based on the communicative process under the specific working environment of language users. Therefore, it needs appropriate communicative functions to achieve the communicative purpose. In order to achieve the communicative function, the use of specific sentence types obviously contains some convention. The characteristics of high-frequency sentence types in international trade letters have a certain tendency. This paper takes the Chinese E-mail actually generated by the Korean staff of a Korean trading company in their trade with China as the research object, investigates and analyzes its sentence function, and provides empirical data for business Chinese teaching. Compared with the teaching of traditional lingua franca, according to the various social attributes of Korean Chinese international trade exchanges, it is not only the cognitive background of learners and staff, but also the communicative context required by professional work. The core content of teaching should give priority to the specific sentence patterns of communicative function words closely related to work in the actual corpus, and apply them in teaching strategies and methods, To enable learners to acquire the required language communicative competence as soon as possible, it does not emphasize the comprehensive mastery of learning, but can save time and selectively improve communication efficiency.