Because of the development of social economy, attentions have been given to human settlements. And the distribution of geographic population is determined by the natural suitability and the restriction of human settlements. Due to most researches focus on evaluation studies of urban human environment and deficiency of research methods chiefly composed by qualitative methods, this paper mainly adopts the geographic spatial evaluation system by RS and GIS to study and evaluate the general conditions of 21 cities or states in Sichuan province from the view of middle scale and natural suitability. Consequently, this paper divides Sichuan into four different zones that reflect different natural living environment: unsuitable area, general suitable area, comparatively suitable area and quite suitable area. The research result of this paper reveals the evolution of the human settlements in Sichuan Province that offer references for decision-making on improving the regional population distribution flow and the living environment.