The Ya'rubi Dynasty enjoys a prestigious rank in Modern Omani History since it witnessed huge achievements, but this did not last for long. It also witnessed a fierce conflict over power that led to critical turning points. This study sheds light over the reasons of the conflict standing on the bases of the Ya'rubi Dynasty represented in the Imamate system and the ruling ways. The study aims also to deduce the role of the Imamate and its enforcement in the Ya'rubi Dynasty, reveal the reasons of internal conflict, identify the reasons of tribal schism; the Hinai and Ghafri, and display the circumestances and results of the Persian interference. The study includes three chapters; the first chapter stands on situation of the Imamate in Ya'rubi Dynasty and stages of development. The second chapter displays the first family conflict and the civil war during the last decades of the Ya'rubi Period. The third chapter traces the second family conflict and the Persian interference. The study depends on on a number of references in the Imamate doctrine and other history references related to the period of the Ya'rubi. The study concludes with several results, most importantly: 1. The study reveals that the Imamate during the Ya'rubi period went through three stages varying in the application of the Imamate principles. Y. 2. It indicates that there are reasons of the internal conflict during the last decades of the Ya'areba period lying on the ruling system of that period. 3. It identifies the reasons of the tribal schism in Oman upon the emergence of the Hinai- Ghafri axis.