文章以B股市场双重审计制度的废除为切入点,研究了管制的放松对审计市场效率的影响。结果显示,总体而言,投资者并未给予积极的反应,不过原先采用同一集团审计模式的公司其市场反应显著好于原先采用不同集团审计模式的公司。进一步研究发现,政策生效之后大部分B股公司放弃双重审计,审计费用随之大幅下降,同时先前实施不同集团审计模式的公司其审计质量和信息环境出现恶化,而原先实施同一集团审计模式的公司却没有发生显著变化。 Based on the abolition of double auditing system in B-share market, the article studies the effect of deregulation on auditing market efficiency. The results showed that, overall, investors did not give a positive response, but companies that used the same group audit model had significantly better market reactions than those companies that previously used different group audit models. Further study found that after the policy came into effect, most of the B-share companies gave up their double audits and audit costs dropped significantly. Meanwhile, the auditing quality and information environment of the companies that previously implemented different group auditing modes deteriorated. However, the companies that originally implemented the same group auditing mode But no significant changes have taken place.