Abstract：At present, as to the study of business English correspondence, domestic scholars mainly study its stylistic features from perspective of stylistics and register theory or writing skills from the perspective of Cooperative Principle and Politeness Principle. However, people have done few researches of positive information conveyance in business English correspondence form the perspective of 7C principles. This thesis applies the method of case analysis to show how 7C principles affect the conveyance of positive information in business English correspondence.

　　　This thesis consists of four chapters. Chapter One makes an introduction to the background of the study, positive and negative information, and the structure of this thesis. Chapter Two deals with previous studies on 7C writing principles and the conveyance of positive information in business English Correspondence. Chapter Three is the application of 7C principles in conveyance of positive information in business English Correspondence. Chapter Four makes a summary, pointing out both the major finds and limitations of this thesis.

Key words: business English correspondence  positive information  7C Principles

摘要：目前对商务信函的研究，国内学者主要是从从文体学、语域理论等研究它的文体特征,或从合作原则、礼貌原则等研究它的写作技巧。然而，大家从7C原则的角度对商务英语信函中正面信息传递的研究还很少。本文通过案例分析的方法来展示7C原则是如何影响商务英语信函中正面信息的传递。

　　　本文共分四章。第一章介绍研究背景，积极信息和消极信息和本文的框架。第二章对7C原则和正面信息在商务信函中的传递的国内研究现状进行了述说。第三章介绍了使用7C原则去指导商务信函中正面信息的传递。第四章是总结分析全文，指出本文的发现和不足两方面。

关键词: 商务信函；正面信息；7C写作原则