At this research we have studied the judicial conflict around Belo Monte´s Dam, judged by Supremo Tribunal Federal (the Brazilian Supreme Court), to understand the relations between discourses of development and constitutional interpretation, in specific, article 231, 3rd paragraph. Our hypothesis was: interpretations that reduced indigenous people´s rights and imposed few condition to the exercise of discretion by public powers would be followed by discourses of development worried about economic growth; on the other hand, interpretation that recognized the indigenous people´s rights to political participation and imposed wide conditions to the exercise of discretion by public powers would not be followed by any discourse of development. Our conclusion partially confirmed our initial hypothesis, as follows: first, there seems to be a trend to less conditions to the exercise of discretion by public powers and reduced rights recognized to indigenous people when discourses of development appears; however, some discourses of development were followed by constitutional interpretations that recognized rights to indigenous people and that imposed wide conditions to the exercise of discretion by public powers.