The aim of this study is to investigates the role of auditor Independence and materiality and risk on audit quality reduction, which is mediated by non audit service. In order to generate the goal of the study, we conduct a survey study at the public accounting firm. We test our 246 usable data from public accountant using Structural Equation Modelling analysis. The results indicate that eirther auditor ethics or materiality and risk had a negative effect on reduced audit quality Replacing and altering of audit process. Otherwise non audit services mediate the relationship between auditor auditor independence and materiality and risk to audit quality reduction.