The new Securities Law will increase the auditor’s liability risk and adjust the audit market structure, which will affect the auditor-client resource allocation and lead to audit governance consequences. From the perspective of auditor-client resource allocation, this paper studies the inhibitory effect, mechanism and audit consequences of the new Securities Law on the influence of auditor-client mismatch on audit opinion shopping, so as to evaluate the audit governance effect of the new Securities Law. Research has found that the downward auditor-client mismatch exacerbates audit opinion shopping, while the upward auditor-client mismatch suppresses audit opinion shopping. The new Securities Law improves the degree of auditor-client mismatch, suppresses the impact of auditor-client mismatch on audit opinion shopping, and enhances audit quality. This study is conducive to decision-making agencies evaluate the implementation effectiveness of the new Securities Law, and has certain reference value for the allocation of audit client resources and regulatory governance of audit opinion shopping.