The purpose of the present study is to investigate the factors affecting AUDIT QUALITY. For this purpose, the concepts of AUDIT QUALITY were extracted using the proposed conceptual model and the factors affecting AUDIT QUALITY including policy making, supervision and operations (including the categories of input, process and output), were identified by systematic approach. The dimensions of supreme council independence, financial reporting requirements, AUDIT institutions size, industry AUDITor, AUDIT fees, corporate governance system, stockbrokers or non-stockholders, thought-based AUDITing, formulating various industry guidelines, AUDITors' perceptions of governance, the use of information technology, and the establishment of a professional supervisory body constitute the conceptual model of AUDIT QUALITY. After identifying and designing the primary model, a questionnaire was developed and distributed among the AUDIT firm's partners. The AUDIT QUALITY measurement model was designed using Structural Equation Modeling and the research hypotheses were identified. According to the results of the research, the AUDIT QUALITY has a moderate positive and significant relationship with the policy making factors in the AUDIT profession and a strong positive and significant relationship with the AUDIT operations. Also in terms of the operational factors, the AUDIT QUALITY has a strong positive significant relationship with the input, and a strong positive significant relationship with processes, and a moderate significant positive relationship with the output; finally, the AUDIT QUALITY has a moderately positive and significant relationship supervisory factors.