The urban development involves more sensitive challenges for evaluation of the urban land use in respect of the framework of sustainable development. In the last three decades, the concept of sustainable development has developed into a broad area that embraces all methods and techniques in different levels of human activities and knowledge gaoling to save energy, time, financial and natural resources. Accordingly, environmental sustainability as a major aspect of the concept has concerned the environmental issues such as: climate change, global warming, waste management, sound masking, etc. The principal goal of this paper is to investigate the role of public squares in new urban developments in the historic cities from the perspective of environmental sustainability. Therefore, the paper considers some examples of the city squares in a case study (Isfahan-Iran) to highlight some problems in adaptation with the new 21 st century-style of urban development in such cities. Hence, the investigation compares the original historic squares vs. some recently developed ones. The literature review of this paper is based on the data gathered from internet, books and journals and previously published conference papers.Moreover, a qualitative research has been conducted through local observation and survey in the location of the case study (Isfahan-Iran). The results will reveal the major principles of environmental sustainability in design of new public squares in such cities. This, in turn, opens new doors to future studies about adoption of old cities with new developments regarding to the concept of environmental sustainability.