Our study highlights the broad outline of the scientific work and personality of Spiru Haret. He was the Romanian education reformer at the boundary of XIX-XX century. To achieve this vision we must note Spiru Haret proposed interdisciplinary science, particularly the relationship between pedagogy and sociology. Within this study we consider the strong scientific and cultural personality of Spiru Haret who anticipate paradigm of social pedagogy. This is substantiated by the author's philosophy, promoted the "Mecanica socială" and its political conception of social liberal with strong accents.