This research investigates the role of nature in residential complexes, in sense of freshness and happiness of residents, by examining case studies in Ekbatan complex in Tehran and mehregan complex in Qazvin. (In this study, happiness was examined from two point of views) The first is subjected to individual and is related to culture, insight and understanding of people and the two views are interrelated and affect each other. Then factors affecting the happiness were studied. It is important to note that the role of nature in creating happiness is basic and undeniable. Nature, as one of the factors in the design of open spaces in these complexes can be useful in the sense of vitality and calm environment and reduction of machine spirit of modernity. Eventually, the impact of nature in Ekbatan and Mehregan complexes were examined through questionnaires the result of questionnaires showed that high level of nature in Ekbatan has very significant impact on sense of happiness of people in the complex, and also the slight nature in Mehregan complex has very little impact on the sense of happiness of people Mehregan complex. According to the concept of happiness and factors affecting it, we shall say, the open nature of the residential complexes, as a gathering place, causes better so social interactions and better relationships between users, which will lead to greater happiness of the residents. In the past architectures, in order to perform these interactions, the naure in the yard was used but, in today`s residential complex, there is less attention regarding meaning and quality of environment. With regards to the requirements of modern life "shortage and sometimes lack of natural elements, rush hours, noise pollution, advanced technology, fading close emotional relations of the resident in most good neighborly relations in residential complexes, and followed by social anomalies(crime) and identity crisis in settlements requires attention to the construction of residential areas with natural elements, for creating space for social interaction(more and better understanding of users towards each other) has attracted researcher`s view. We can also say, nature as factor that can canes social, cultural, psychotically mobility of people in residential complexes, has been considered in this study. And according to the belief that man is part of the nature, causes his survival, and this valuable relationship is emphasized is emphasized in Islamic teaching is one of the main points in this study the methodology described in this research is qualitative.