Audit risk by the inherent risk factors, such as the conduct and ability of management, industry and their environment, nature of business, prone to misstatements of financial statement items, vulnerable to loss or misappropriation of assets as a result of the risk, but also by the internal control risk factors World pipe network reported that the world's steel pipe network to provide the world's steel pipe network editor , account balances or types of transactions, there are misstatements, internal controls failed to prevent, detect or correct the risk, in addition, also failed to find accounts by certified public accountant to perform the audit procedures balance or types of transactions to misstatement risk profession soon developed an audit risk model. Audit risk model and theory to solve a certified public accountant to the system based on random sampling audit World Steel Pipe News , but also the allocation of audit resources to require the certified public accountant to audit the allocation of resources to the most likely to lead to the accounting statements of material misstatement areas. From a methodological point of view, the certified public accountant to audit risk model based on the audit, known as risk-based audit approach (riskoriented audit approach).