本研究主要探討準強制性會計師輪調機制與客戶公司審計品質(以盈餘反應係數為代理變數)的關聯性，並藉由檢視在此機制下有進行會計師輪調之公司與未進行會計師輪調之公司的盈餘反應係數、會計師輪調後後續年度的盈餘反應係數以及採行所間/所內會計師輪調的盈餘反應係數來檢視準強制性會計師輪調機制對審計品質的潛在影響力，進而瞭解該機制的實施成效。 本研究發現，雖然迴歸結果顯示有進行會計師輪調樣本之盈餘反應係數大於未進行會計師輪調樣本的盈餘反應係數，投資大眾認為有進行會計師輪調之公司其審計品質優於未進行會計師輪調之公司，與本研究之預期方向相符；但由於結果並未達顯著水準，表示在投資人心中，準強制性會計師輪調機制並未對公司審計品質造成太大的影響。就輪調之後續年度審計品質變化而言，在輪調後第一年及第二年的盈餘反應係數較輪調當年度為低；雖然結果不顯著，卻顯示市場認知的審計品質在會計師輪調後初期有下降的現象，可能是投資人認為繼任會計師在查核初期對受查者事業的不熟悉，將導致審計品質下降所致。 就事務所間輪調與事務所內輪調之效果而言，本研究的實證結果指出投資人認為在應輪調年度採行會計師所間輪調較所內輪調更能提昇審計品質，但結果亦不顯著。至於在所間輪調下，事務所規模是否會影響審計品質之問題探討，根據所間輪調樣本的營運狀況與財務比率，本研究發現選擇將查核會計師由非四大會計師事務所更換至四大會計師事務所的公司擁有較佳的營運狀況與財務體質，與大眾直覺及預期相符。 / This study is mainly discussing the association between quasi-mandatory auditor rotation system in Taiwan and the audit quality (use earnings response coefficient, ERC, as proxy) of company by examining the ERC of companies that do not rotate their audit-partner versus companies that rotate their audit-partner under this system, analyzing the change of ERC in the follow-up years after audit-partner rotation, and comparing the difference of ERC between audit-firm rotation and audit-partner rotation. The empirical results indicate that, although insignificant, investors perceive the audit quality of companies which rotate their audit-partner is better than the audit quality of the companies that do not rotate. This means, in investors’ thought, the quasi-mandatory auditor rotation system doesn’t work in audit quality promotion. For the change of the audit quality in the years after audit-partner rotation, this study finds out the audit quality the market perceived will go down in the first and the second year after audit-partner rotation due to the successors’ unfamiliarity with their clients. Furthermore, the result insignificantly points out that the public think audit-firm rotation is more useful in audit quality improving than audit-partner rotation. As to the question that whether the scale of audit firm influence audit quality, the evidence from the operation data and financial ratio of audit-firm rotated sample in this study suggests that the companies which rotate their audit-partner from non-Big4 to Big4 have superior operational performance and sounder financial condition than companies rotate their audit-partner in other ways. This result is consistent with the intuition of the public and the expectation of this study.