Abstract: First the two method used to determine the standard for judging auditing materiality are discussed, they are:the fixed-ratio method and the varied-ratio method.And then it is pointed out that the standard for judging auditing materiality affects the auditing risk. The risk meeds to be reduced by following appropriate auditing procedure.Besides in practice certified public accountants (CPAs) should not only consider the effect of auditing materiality on the planning and exercising an auditing programme but also consider its effect on the type of report that auditor is to make.