中國註冊會計師協會為提升境內事務所之規模與品質，推動「會計師事務所做大做強」計畫，該計畫促使中國會計師事務所展開合併風潮。但會計師事務所透過合併擴張規模的同時，其經營效率是否亦有所提升，尚未有文獻分析。本文以資料包絡分析法分析會計師事務所之經營效率，並以麥氏生產力指數分析事務所經營效率之變化。實證結果顯示，涉及合併的事務所跨期間經營效率的提升較未涉及合併的事務所高。本文進一步將涉及合併的事務所依據合併前是否具有「證券、期貨相關業務許可證」加以區分，發現兩家以上具有證券、期貨相關業務許可證之事務所合併，對於經營效率的提升才有顯著正向的影響。此外，本文將合併前事務所總所所在地是否在同一省份加以區分，實證結果顯示，若合併前事務所總所位於不同省份，事務所間業務區域互補性高，對於事務所經營效率的提升有顯著正向的影響。綜上所述可知，中國近期涉及合併事務所的效率提升較未合併者顯著，但並非所有事務所都可以透過合併來達成做大做強的效果，在推動政策與事務所在進行合併決策時，應審慎評估事務所合併對於經營效率的影響。

Developing larger and more competitive Chinese CPA firms is the objective of Chinese government. The Chinese government supports CPA firms to achieve scale growth through merger. This study examines the relationship between operational efficiency and the merging of CPA firms. We measure operating efficiency by applying Data Envelopment Analysis (DEA). Using revenue and human resource data in China for the 2004-2009 period, we find firms that are involved in mergers have significantly higher productivity growth than their peers. However, not all mergers have positive effects. Mergers occur between two (or more) CPA firms that are licensed to audit listed companies and mergers occur between two (or more) CPA firms that headquarter are in different provinces have significantly higher productivity growth. The findings of this study have policy implications for regulators in China and the Chinese CPA firms.