本研究以2007年至2011年中國滬深交易所A股上市公司為研究樣本，以中國證監會公佈之行政裁罰、深滬兩交易所對上市公司之處分、及企業自行揭露的內部控制評價報告之內容分析企業發生內控缺失之類型，依照中國《企業內部控制基本規範》，將內部控制缺失依內控五大要素與五大目標予以分類彙總。並將企業的投資效率分為投資不足與過度投資，分別探討內部控制有效性對公司投資效率之影響。 實證結果顯示投資不足的程度與可靠的財務報導之內控目標的內控缺失存在正向的顯著關係。而過度投資的程度與是否發生內控缺失、後勤支援活動和內控設計及執行的內控缺失類型、內控五大要素、及營運的效率效果之內控目標的內控缺失呈現顯著或單尾顯著的負向關係。整體而言，在被監管單位揭發內控缺失資訊，內控有效性較低，而自我揭露愈多內控資訊，企業內控意識可能較佳之假設下，內控缺失一定程度影響企業的投資決策，內控的有效性有助於投資效率。 / Based on the sample of A-share listed companies in China over the period of 2007-2011, the research classified the companies by under investment and over investment, and investigated the impact of internal control efficiency on firm investment effectiveness separately The study comprehensively collects internal control reports released by listed firms and collects penalties which are released by the China Securities Regulatory Commission (CSRC), the Shanghai Stock Exchange (SSE) and the Shenzhen Stock Exchange (SZSE). A further classification of internal control weaknesses was performed based on the nature of the events, COSO Internal Control — Integrated Framework and regulations of internal control in China. 　　In sum, the empirical results indicate that, for the companies under investment, the internal control weaknesses of financial reporting have significant positive impact on firm investment effectiveness. On the other hand for the companies which were over investment, those with internal control weaknesses have significant negative association with investment effectiveness. Moreover, the results show that companies with defective of logistics work or the design and execution of internal control were worse performers on investment effectiveness. Based on the COSO framework, the internal control weaknesses classified by the elements, including control environment, risk assessment, control activities, information and communication, monitoring, and the efficient and effective operations of the internal control objective are significant or one-tailed significant negative correlated to firm investment effectiveness. Collectively, if the internal control weaknesses were disclosed by the authorities, the firms had worse internal control efficiency, while the firms which were more conscious of internal control would disclose the internal control weaknesses themselves. The study shows that internal control weaknesses have impact on firm investment policy, and that internal control efficiency helps promote firm investment effectiveness.