This research deals with the civilizing role of Omani people in East Africa during the era of Sayyid Said bin Sultan , the most famous ruler of The Busaidi state. The economical side has been particularly chosen as a civil factor in East Africa during the first half of nineteenth century. The most renowned economical activities which were carried out by Omani people in Zanzibar and its surroundings, were agriculture and trade which were the backbone of the whole economical activities, and the latter in particular has the lion share of this research. In consequence of this intensive economic activity, the Omani influence became very obvious in all political ,cultural and social aspects in East Africa. In the introduction the objectives of selecting this subject are: demonstrated and all the sources , references and documents , which served the research project , are displayed . The study plan consists of five chapters beside the introduction, foreword and conclusion. The first chapter deals with agriculture, the "second chapter covers the trade , the third chapter tackles the foreign trade relations, the fourth chapter discusses the economic policy of Sayyid Said and the final chapter examines the results of economical activities in East Africa. As a conclusion I briefly revealed the most important results of this economic activity in East Africa , then finally an appendix followed by the list of sources and references.