| In various countries of the world, Merger and Acquisition (M&A) of listed companies have always been focused. Whether M&A can improve performance effectively or not has aroused the domestic and foreign academic enormously attention. At present, there are a large number of theoretical studies on M&A performance .In general, the value of M&A effect is uncertain. In order to study the impact of M&A to Chinese listed companies, the thesis attempts to inspect the performance of listed companies during the M&A years by empirical study.The dissertation summed up the conception of M&A, motivation, and the meaning of performance of M&A on the basis of former research results. It decided to use financial evaluative measure for evaluation after compared two evaluative measures of performance of M&A. It takes 112 listed companies as the samples that have experience M&A in 2004, selects five financial indexes to evaluate the performance of M&A, then sets up integrated-point-function model by analyzing factors on this foundation, it examinate the performance of M&A by Using different synthesis scores with Paired Sample T Test .Though comparing integrate performance score of M&A, it inspects the fixe-year performance changing of whole samples., and analyze the influence factors of M&A performance.The research showed that performance of M&A always improved at the first, but the level of performance descend subsequently. Whether the acquirer obtaining the control rights of merged companies do not have any noticeable effect on M&A'S performances.The performance of the relating M&A is superior to the irrelating M&A. There is no correlation between the largest shareholder's ownership propotion with M&A'S performances.Finally, based on the above empirical analysis, author brought forward some Countermeasures that the listed companies in china should consider the long-term interests of study was a must. The enterprise should strengthen integration with target companies during or after M&A activities and bring the advantages of both sides into full play. Government of all levels should not interfere with the M&A activities of listed companies; Securities regulatory organizations should strengthen the supervision. |