This study, carried out in the streets of Lomé, made it possible to explore the psychological aspects of street children on the one hand, and then to analyze the impact of psycho-affective development on the defence mechanisms they adopted. We started from the hypothesis that street children who have not received strong emotional support in childhood use aggressive defense mechanisms to survive on the street. To collect our information, we selected children in street situations aged 10 to 19, who had spent at least three months on the street with any family breakdown and who were present on the three sites planned for our survey, such as Kodjoviakopé, Agoè Zongo and Hollando on the days of the interviews. Using an interview grid, the Rorschach projective test and the Rosenberg scale, the information was collected and then analyzed using the quantitative and qualitative method including content analysis. The results obtained show that in the process of psychoaffective development, attachment experiences influence the ability to negotiate and form compromises in interpersonal relationships and in the choice of psychic defense systems. In our sample, we find a workforce of 95.23% with child needs and 85.71% with conflict management difficulties. To get out of this impasse a little, the ESRs in particular withdraw into themselves with a tendency to stifle their emotional lives. (That’s 80.95% of our sample). The quality of psycho-affective development leads to the adoption of particular defense mechanisms. Despite the fragility of their daily lives, these children in street situations demonstrate an astonishing inner strength that allows them to cope with the harsh conditions of life on the street.