Following the fall of Bukhara at the hands of the Mongols, Sayyid Ajall, Umar Shamsiddin, a descendant of Imam Zaynilabidin, migrated to China achieving great social positions and rendering invaluable service to the Chinese people. From the historians' point of view, the most important factors for the spread of Islam in the Chinese province of Hunan had been the eminent characters of Sayyid Ajall and his son. This article deals with the different aspects of Sayyid Ajall's social life and his services to the Chinese people in four parts: A. Sayyid Ajall's social and managerial positions B. Sayyid Ajall's services to the Chinese people, especially to the people in Hunan C. Factors for the spread of Islam in China and Sayyid Ajall's role D. Reasons for Sayyid Ajall's progress and success.