The literature distinguishes two types of psychotherapy researches: studies on effects and studies on processes (Hill & Lambert, 2004). While the first focuses on the effectiveness of therapy, the second looks at 'how does psychotherapy work” (Strupp, 1992; Hendrick, 2009). Our research focuses on the evaluation of the therapeutic processes in crisis intervention by trying to answer the question: how crisis intervention works? Our scientific and clinical approach has led us to work with 16 experts in crisis intervention. The qualitative analysis called Grounded Theory Methodology described by Glaser and Anselm Strauss (1967) was used to better explore the therapeutic techniques used in the clinical practice. Various steps of our qualitative research and our first results willbe exposed. The aim of our study is to redefine the concept of crisis and to modelize the techniques implied in the therapeutic processes of crisis work.