On the basis of drawing lessons from the existing research results both at home and abroad , this paper observes the change law of the two financial indexes of nroa and croa from 1997 to 2001 , studies the relations between the locations of listed companies and the m & a performance , between the structure of equity of listed companies and the m & a performance , between the industry nature of the listed companies and the m & a performance , between the type of m & a and the m & a performance , and then draws several conclusions that m & a performance is unsatisfactory on the whole , m & a performance of listed companies in eastern china is superior to that of the counterpart in middle or western china , m & a performance of listed companies that the country or the other corporations hold the most share of the listed companies is unsatisfactory on the whole , the growing or mature listed companies can achieve best m & a performance when they implement the m & a horizontally while the listed companies in declining phase may perform the conglomerate m & a the best 在借鉴国内外已有的研究成果的基础上，本文考察了并购上市公司从1997年到2001年五年时间内净资产收益率和主营利润率两项财务指标的变化规律，研究了并购公司所在的区域与并购绩效、并购公司的股权结构与并购绩效、并购公司的产业性质与并购绩效、并购类型与并购绩效等方面的关系，得出了若干结论： 1 、并购绩效从总体上来说是不理想的； 2 、东部上市公司的并购绩效要优于中部和西部上市公司的并购绩效； 3 、国家股或法人股是第一大股东的上市公司的并购绩效不理想； 4 、处于成长性产业和成熟性产业的上市公司发生横向并购绩效最好，处于衰退性产业的上市公司发生混合并购绩效最好。
Given the historical background and system arrangements , their intimate connection is examined and policy implication on shareholding structure is presented according to the statistical results . as a result , we find the following results : first , it is shown in the empirical study that an over - diversified shareholding structure may lead to the " free rider " problem and the relative concentration of the shareholding is beneficial to the enhancement of firm value . second , the relative control by the legal person is beneficial to the enforcement of corporate governance in the chinese listed firm ( 2 )股权相对集中有利于提高我国上市公司价值；国家股比例对公司价值的影响不显著；法人股比例与公司价值成u型曲线关系，当法人股比例在0 35 . 05之间时，公司价值随法人股比例的上升而增加，当法人股比例超过35 . 05时，公司价值随法人股比例的上升而下降；流通股比例与公司价值成负相关。
