会计盈余与现金流量的信息含量的研究具有重要的意义。自Ball and Brown开始，这类的研究逐渐增加而日趋成熟，但所得结论尚不一致。本文选择沪市2006年到2008年的A股制造业上市公司为样本，其中，2006年符合条件的公司有657家，2007年有652家，2008年有652家，共计1961个样本。为保证累积超额报酬率的变动主要来源于年报的公告，本文采用事件研究法检验累计超额报酬率与未预期会计盈余及未预期经营性现金流量之间的关系，并且检验未预期会计盈余与未预期经营性现金流量的信息含量是否存在显著差异。结果发现，从2006年到2008年，会计盈余和经营性现金流量对股价的影响都不显著。不同的是，未预期营业利润对累计报酬率的解释力在逐渐下降，而未预期经营性现金流量对累计报酬率的影响在逐渐增加。根据Vuong检验的结果，会计盈余与经营性现金流量的信息含量没有显著差异，即现金流量没有提供增量信息。

The researches of information content of accounting earnings and cash flows have significant meanings to investors. So far, this kind of research has been more and more mature, however, no agreement has been reached. This paper decides to use the data of companies in manufacturing industry which are listed on Shanghai Stock Exchange from 2006 to 2008. There are 657 companies in 2006, 652 companies in 2007 and 652 companies in 2008, which confirm to all the conditions. In all, there are 1961 companies. To make sure that CAR(cumulative abnormal returns) is only affected by unexpected accounting earnings or unexpected cash flows of operation, this paper tries to discuss the relationship between CAR and unexpected accounting earnings(or unexpected cash flows of operation by event study. The result shows that there isn’t an apparent relationship between them. The explanatory power of unexpected accounting earnings decreases by year, however, that of unexpected cash flows of operation increases. At last, according to the result of Vuong Test, there is significant difference between the information content of accounting earnings and that of cash flows of operation. In another word, cash flows don’t afford incremental information.