Art therapy has unique factors that are different from those of other counselling and therapy. Thus, case-conceptualization that is appropriate for an art therapy must be different from case-conceptualization for general counselling and therapy. This research studied the process of case-conceptualization, in the same way art therapists conceptualize a client’s problem at the therapy field, the way they plan for the therapy and the way the evaluation of cases takes place. Through a purposeful sampling, in-depth interviews were conducted on 9 professional art therapists and data were analyzed by applying an inductive theme analysis. Through the data analysis, 25 concepts, 11 sub-categories and 6 categories were founded. The categories of art therapist s experience of case-conceptualization process are: “understanding the necessity of case-conceptualization,” “It was found that the components for a case-conceptualization are not appropriate,” “the limitation of art therapy case-conceptualization,” “the reality of art therapy case-conceptualization,” “the understanding of client’s problem’ and ‘the finding of an appropriate case-conceptualization for an art therapy.” Based on these categories, the significance and limitation of this research were also discussed.