Business correspondence is one of the most important business tools. They are used for keeping in touch with company's customers and the close social, business relationship. It also gives a company a competitive edge and offers marvelous results. After graduation, students will become a business person. Business correspondence is used in their working environment every day. An effective business letter can give them opportunities to quickly get ahead in their career. “Business correspondence” is a subject in the syllabus in our university. Surveying the studying situation, our students find it very difficult for writing the kinds of letters. One of the reasons is that students have no real experience in writing. Writing a right business letter is challenges for them. How to write an effective business letter, what are common errors made and how to solve the problems are the purposes focused on in four parts of the presentation.