The space under the Velayat Bridge is one of the most important lost urban spaces in Tehran, due to its adjacency to important areas of activity and residence. In recent years, the area under the Velayat Bridge has been repeatedly prepared for executive operations, but so far, no action has been taken. Currently, illegal acts are very common in this area and at nights security indicators are decreased significantly. This study based on qualitative approach and survey research methodology, tries to identify and evaluate physical, psychological, environmental and mental factors which affecting the process of reviving the lost urban space under the Velayat Bridge. Basis for identifying effective factors is the theory of the right to the city. Data gathering was done through library studies as well as survey methods such as observation, interview and distribution of questionnaires. In this study, four hypotheses have been proposed and tested. Finding results show that all variables including physical-structural, activity-social, environmental and semantic perceptual indicators are significant, as their error level is lower than 0.05. Physical-structural index variable with beta coefficients of 0.851 has the highest effect on the design variable of the space under Velayat Bridge. According to the answers of the respondents, it seems that the construction of a commercial complex and also the transformation of open space into the space of human presence, taking into account the age, gender and different needs of people, can be the most effective action to revive this space. پرونده مقاله