With the advent of the global economic integration pattern, business English writing has become one of the important means of trade. Business writing is a powerful assistant to economic activities and economic work, and a tool and weapon that economic workers and other relevant personnel must master. At the same time, Business English Writing is a course that develops and improves the professional writing skills of Business English students, and is an important part of the Cambridge Business English Test. Wrong or irregular business English writing will bring unnecessary misunderstandings and troubles to enterprises and countries. Therefore, how to accurately grasp the method of business English writing will become a particularly important ability. However, at present, most professional students still have many problems in the process of writing business English, which is prone to the wrong format of writing letters, Chinese English, and grammatical errors. This paper proposes relevant solutions to the common mistakes in business English writing from the 7C principles of business English writing violations. Thereby improving the writing ability of business English majors, making them perform well in business occasions and business English exams.