This paper concerns a clinical research about sex-offenders adolescents, financed by French Ministry of Justice. The research is based on a population of 20 young boys and girls from 13 to 17 years old. The personality assessment is based on projective methods (Rorschach?s test and T.A.T). This paper will present the main results of this research, in the project to consider violent sexual acts in psychodynamic understanding. All the results allow to differentiate two groups of sex-offenders adolescents, in accordance with the age of the authors and the victims, the types of acts (done alone or with other one) and repetition or not... Through the analysis of these two groups appear significant psychodynamic differences about violent sexual acts meaning in the way of adolescent?s process.