自2005年開始PCAOB對外國之註冊會計師事務所進行國際檢查，至今已逾十年，然而制度實施之初面臨許多質疑。而今，已有文獻指出不論是美國或是其他國家，PCAOB的檢查皆具有一定效益，且具有外溢效果。惟各國間的國家特性因素於目前文獻中尚有發展空間，因此本研究欲了解國家特性是否會影響PCAOB國際檢查的外溢效果。 　　本研究以2004年至2013年間35國的資料計算裁決性應計數，以此代理審計品質，觀察各國審計品質於檢查前後的變化，並以法規執行力以及四大會計師事務所市占率代理國家特性，進一步了解不同特性的國家，其審計品質改變幅度的差異。 　　根據實證結果發現，當一國的法規執行力較高或是四大會計師事務所市占率較高時，審計品質較佳，因此於PCAOB國際檢查後審計品質提升幅度較小。各國的準則制定機構可透過本研究的國家分類，量身訂定更符合國家的準則，以改善審計品質。 / Since 2005, PCAOB has inspected foreign registered audit firms for a period over ten years. The benefits of inspection in both the United States and other countries are documented by extant literature, but the research of country characteristics on the spillover benefits is still lacking. In this study, we document how country characteristics influence the spillover effect of PCAOB international inspection on audit quality. This study uses discretionary accruals as the proxy of audit quality. Our data of non-US-listed companies from 35 countries during 2004-2013 are taken from Datastream. In addition, we use legal enforcement and Big 4 dominance to investigate how country characteristics affect the magnitude of audit quality changes. According to empirical results, we find that countries with higher legal enforcement or Big 4 dominance provide better audit quality. Therefore, PCAOB international inspections in these countries generate smaller magnitude of audit quality improvement than in countries with lower legal enforcement and Big 4 dominance . Our results suggest that regulators of different countries should develop more tailored regulation in order to improve audit quality of their respective countries.