developing science in North Sumatra, then researchers will look at the role of educational institutions in the development of Islam in North Sumatra. And then the researcher wants to know the influence of Ulama in calling Social changes that occur in the people of North Sumatra. The method used in this research is descriptive qualitative research, which aims to understand social problems, events, the role of interaction and community groups. The qualitative approach is used by focusing on the social conditions surrounding the existence of the Ulama who lived in his day, which became the basis in compiling the historical events of the ulama network in the development of Islam in North Sumatra in the XX century. The results of this study are First, the scientific network among fellow North Sumatra scholars is very good, it shows from the shape of the education system. This can be seen in the connection with his teachers in the Middle East. Secondly, the role of Isl?mic boarding schools Musthafawiyah and Maktab Islamiyah is very important, including as a producer of scholars in North Sumatra and a center for the study and development of Islamic Law studies in the midst of society. Third, the Ulema continue to maintain Islamic treasures as a source of answering all problems of social change. As the second answer emphasizes, one of the central roles of the pesantren is to become a center for the study of Isl?mic law studies. Keywords: ulama network, Sumatera, development, the 20th century