Historical monuments in Morocco represent a heritage, of great value in terms of its history, culture, civilization and identity. This heritage is a non-renewable resource considered as one of the essential aspects of modern communities and contributes to the sustainable development of the country. Unfortunately, these monuments are subject to pathologies due to several factors that threaten its sustainability. The choice of the type of intervention thus becomes a strategic decision that has a crucial impact on the historic monument. Indeed, it requires a global approach because it involves simultaneously a multitude of stakeholders and a multitude of criteria (technical, environmental, social, political or administrative, human etc …). Several models in the literature have focused on the multi-criteria decision support process. This work proposes a decision support method based on the Analytic Hierarchy Process (AHP) method, in order to apply it to a choice of an intervention strategy on historic monuments. Then, this approach is applied to the case of the enclosure of the old medina of Salé.