The primary objective of this study is to identify what factors affect the assessments of the auditor's risk including audit risk, business risk, and personal risk in under-researched area of Taiwan. Factor analysis and logistic regression were selected as being analysis methods. The result shows that three factors including the effectiveness of control activities, reporting bias of management and reliability of management are strongly associated with identified risks' assessment, which indicates that the client's control environment dominates auditor's risk assessment.