This study aims to analyse the relationship between the abnormal audit fees and the audit quality by including the moderating variables which are related to business characteristics such as client complexity, audit report lag, audit committee independence and audit rotation. Based on 225 firm year observations through the time period 2017 to 2021 the study revealed that abnormal audit fees have no effect on the audit quality, i.e. the mean of abnormal audit fees in this study close to zero so it will not has a great effect on the audit quality because the lowest value of the abnormal audit fees of my study sample. But the business characteristics may have great effects on the relationship between the abnormal audit fees and the audit quality, because the firm characteristics may lead to more effort so the abnormal audit fees in this case will be explained, hence the relationship between the abnormal audit fees and the audit quality can be moderated by the business characteristics. In this context, we found the interactions with the abnormal audit fees and both audit committee independence and audit rotation have positively significant effect on the relationship between the abnormal audit fees and audit quality, so those business characteristics that related to the audit committee independence and audit rotation can moderate the relationship between the abnormal audit fees and audit quality. In addition the other business characteristics which are related to client complexity and audit report lag have no effect on the relationship between the abnormal audit fees and audit quality