This paper`s aim is to analyze the changing structure of the Eastern Roman Empire`s administrative system and its ruling elites of the sixth century. On the basis of this analysis, the present work interprets the impact of emperor Justinian I`s reforms of the imperial integration; and its meaning for the development of the Byzantine state and society from the seventh century on. The first imperial reform involves changing the senatorial class. Senators had been too privileged since the fourth century. By expanding the class of “illustres”, the emperor downgraded the status of the old senatorial aristocracy. Also, by creating new higher titles such as “gloriossus” and “magnificus”, he promoted the faithful servants of his inner circle to the top administrative positions. Therefore, the new aristocracy based on public service and allegiance to the emperor could emerge from the seventh century on. The second imperial reform was to simplify the complex fiscal administration (operated at three level units) by removing the intermediary diocesan level`s apparatus. As a result, the civil administration was made into two level units: prefectural and provincial. Thanks to this innovation, the ‘Largitiones’, an independent financial department, could be declined to be integrated into the fiscal sub-departments of the prefecture of the Orient during the seventh century on. The third imperial reform covered integrating the ancient urban institutions into centralized provincial governance. While protecting cities and their autonomy, the emperor strengthened the provincial governor`s financial and military authority. As a result, municipal independence declined while the central supervision of the urban population increased. Thus the imperial church played an increasingly important role in city affairs and also local troops could be established in and around the cities. It was the first step of the creation of new byzantine provincial administration from the seventh century on.