Professional skepticism (PS) is one of the key points in audit quality. There are several motivations and barriers to professional skepticism in the audit process. The purpose of this study is to make clear and to compile motivators and effective barriers on auditors'  PS and to identify its consequences through grounded theory approach that can improve an active and continuous process of PS and thus the result is audit quality. This study is qualitative research. So an interview with 16 individuals, whom associate audit institute and the public managers of Iranian auditors which are chose through purposive sampling approach and Snow Ball approach in 2019. Sampling was continued until saturation of theory in the process of collecting data. To gain validity and reliability of the research, there are some methods used to validate the qualitative research and the model such as: consensus / triangulation, evaluation through members, evaluation based on 10 criteria of acceptability proposed by Strauss and Corbin. Then, the motivators and barriers of PS of auditors in caused situation, in obstacle condition and motivator situation   was analyzed and through noticing  the paradigmatic model of the process of auditors' PS formation its results include effective consequences (control aspect and Accreditation aspect) and behavioral consequences (economic discipline and response).