本文在分析规模经济和代理成本对会计师事务所审计质量影响的基础上,建立了关于事务所规模和审计质量控制完善程度的审计质量函数,通过分析推导得出在我国目前审计市场中存在“审计盈亏平衡点”的结论,且在该“平衡点”处审计质量最高。并提出了在我国目前审计质量控制尚不完善的审计市场中,“中等规模的会计师事务所理论上拥有最高的审计质量”的观点。 Based on the analysis of the influence of scale economy and agency cost on the auditing quality of accounting firms, this paper establishes the auditing quality function on the auditing scale of firms and the quality of audit quality control. By analyzing and deducing, Breakeven point “conclusion, and in the” balance point “at the highest quality audit. And put forward in our country audit quality control is not yet perfect audit market, ”medium-sized accounting firm in theory has the highest audit quality" point of view.