近幾年來，財務弊案層出不窮，管理當局參與創造性會計的情事日益嚴重，資本市場陷入紀律危機，徒增成本。為喚醒投資者對於盈餘品質的關注，以及對盈餘管理有更客觀的瞭解，本研究提出兩種不同基礎之盈餘品質分類法，並探討台灣上市公司在盈餘品質分類法下，財務特性與盈餘管理成分的差異。 以往國內文獻多個別探討盈餘品質的內涵，或盈餘管理的現象；將盈餘品質與盈餘管理兩大主題做結合，乃新嘗試。研究主要分為兩大部分，第一部份定義盈餘品質，而第二部分深入盈餘管理的課題。 研究以2002年第3季到2004年第3季，381家台灣上市公司，共3429個樣本點，進行迴歸模型分析。 首先將樣本以：一、盈餘對營運現金流量的關係，及二、應收帳款成長率對營收成長率的比較，共兩種基礎，區分盈餘品質。在區分盈餘品質後，以盈餘品質測試盈餘評價能力與持續性。發現以盈餘對營運現金流量關係作為基礎之盈餘品質，具有增額評價能力，而以應收帳款成長率對營收成長率的比較做為基礎者，無增額評價能力。而兩種盈餘品質對盈餘持續性有顯著貢獻。 第二部分將樣本分為盈餘平滑企業與非盈餘平滑企業，探討盈餘評價功能之強弱，發現在盈餘平滑與盈餘非平滑兩組別中，盈餘平滑化並不影響盈餘評價能力。接著導入盈餘品質，觀察在交叉分組下盈餘評價功能的差異，發現高盈餘品質結合盈餘非平滑化（Quality Non-Smoother）的組別中，有最高盈餘評價係數。盈餘進一步拆解成三個組成份子：營運現金流量，裁量性應計數，與非裁量性應計數。其中，觀察重點在於裁量性應計數，研究同樣加入盈餘品質，測試其評價能力與持續性。發現裁量性應計數具有評價功能，而在兩種盈餘品質指標分類下，高盈餘品質之裁量性應計數，並無增量評價貢獻；在持續性方面，兩種盈餘品質指標同樣對裁量性應計數有正向貢獻。 為測試盈餘品質在盈餘管理誘因下的反應，最後將盈餘管理誘因區分為達成損益兩平與超越前期盈餘兩項目標，並加入盈餘品質，觀察其交互作用。發現在「達成損益兩平」與「超越前期盈餘」兩種盈餘目標下，盈餘管理現象的確存在。加入盈餘品質變數後，在兩種盈餘品質變數之作用下，對「達成損益兩平」與「超越前期盈餘」兩項管理誘因均有抑制作用。 / During the last few years, there have been numerous cases of financial ma-nipulation and scandals of firms and the situation of the managing authority par-ticipating in creative accounting has become worsen which has posed enormous disciplinary risks and unnecessary costs on the entire capital market. In order to invoke the concern of investors towards earning quality and to objectively under-stand more broadly about earning management, this study focused on two dif-ferent earning quality categorization based on different basis. The other aim of this study was to discuss the differences of financial characteristics and earning management that arise under two different earning quality categorizations. Most of the local existing literature discussed separately on the essence of earning management or the phenomenon of earning management; this study would be a completely new attempt, which combined the above-mentioned two topics into one study. The first part of this study focused on the definition of earn-ing quality and the second part discussed in detail on issues concerning earning management. A regression analysis was conducted on 381 publicly listed firms in Taiwan during the period from the third quarter of 2002 to the third quarter of 2004 and the total sample points were 3429. Firstly, the samples were processed and the samples’ earning qualities were categorized based on: 1. the comparison between earning and operating cash flow; 2. the comparison between the growth rate of account receivables and the growth rate of revenue. After the categorization of earning qualities, earning qual-ity was used to test the ability of earning valuation and the persistence of the earning. It was revealed in this study that the earning quality based on the com-parison between earning and operating cash flow could greatly enhance the abil-ity of earning valuation. On other hand, the earning quality based on the compari-son between the growth rate of account receivables and the growth rate of reve-nue failed to enhance the earning valuation. However, both categories of earning qualities had significant contribution to the persistence of earning. The second part of the study separated the samples into earning smoothing firms and non-earning smoothing firms in order to discuss the power of the ability of earning valuation. The results showed that earning smoothing did not have any impact on ability of earning valuation. The next step was to introduce earning quality into this part of the study and to observe the differences in the ability of earning valuation that arise from cross grouping. It was revealed that the group of high earning quality combining non-smoother had the highest earning valuation coefficient. Earning was further decomposed into three components: operating cash flow, discretional accruals and non-discretional accruals. The focus was on the observation of discretional accruals, and in this part of the study, the earning quality was also introduced in order to test the ability to valuate and the persis-tence of earning. It was discovered that discretional accruals possessed the func-tion of valuation. Furthermore, under the categorization of earning quality indexes with two different bases, discretional accruals with high earning quality had no contribution toward the ability to enhance valuation; however, about the persis-tence, both earning quality indexes had positive contribution toward discretional accruals. Finally, in order to test the reactions of earning quality under the influence of the incentives of earning management, the incentives of earning management were categorized into two groups with two different goals: 1. to reach breakeven; 2. to exceed prior period earning. The earning quality was also introduced to ob-serve the interactions. It was observed that under the two different goals in earn-ing, the phenomenon of earning management did indeed exist. After including the variable of earning quality, under the influences of two different categories of earning quality variables, there was some kind of suppressive effects on the management incentives of “reaching breakeven” and “earning that surpasses the prior period earning”.