本文从长园集团反并购的案例研究出发，首先介绍了长园集团的公司情况、反并购的过程。依据沃尔核材的并购行为特点将其定性成敌意并购进行分析。引入动态博弈模型，分析长园集团实施的各项反并购策略。通过事件研究法定量评估长园集团实施的各项反并购策略产生的市场反应，考虑后续长园和鹰的业绩造假，以及商誉结果，综合评判反并购策略效果。最终得到研究结论，并从监管机构、无实控人企业两方面提出研究建议。

首先，利用动态博弈模型，得到博弈均衡结果是长园集团实施的焦土战术和出售冠珠等策略改变了动态博弈的精炼纳什均衡，使沃尔核材放弃继续并购。进一步分析在不同策略情况下对均衡结果的影响。

其次，通过事件研究法分析可知，长园集团的有效阻止沃尔核材并购的反并购策略中溢价并购的短期市场反应最好，但是长园集团管理层为被并购企业支付了与其发展潜力不相符的高额溢价，为后续长园集团市价大跳水埋下祸患。而修改公司章程的行为虽然有效增加了沃尔核材夺取长园集团控制权的难度，同时也使投资市场的外部投资者质疑管理层权力是否过大从而损害股东利益，影响了长园集团的股价。

最后，得到两个维度的启示，对于监管部门要下调关于投资者增持无实际控制人企业股份的公告提示线，以及加强对企业的信息披露制度的监管力度。对于目标企业要增强敌意并购的防范意识，选择目标一致，合作中有更高约束力度的白衣骑士，完善内部治理机制，预防管理层审查失职，保护无实控人企业中小股东的知情权，防止管理层出于自利目的而损害投资者利益。

Based on the case study of anti-m & A, this paper first introduces the target company's situation, the process of anti-m & A and analyzes the M & a behavior of the acquirer as hostile M & A. Then the dynamic game model is introduced to analyze the target company's anti-m & A strategies. The effect of anti-m & a strategy is evaluated quantitatively by the event study method, considering the performance fraud and goodwill of the subsidiary company. Finally, the conclusion of the study, and regulatory agencies, enterprises without real control and small and medium-sized investors these three research recommendations.

First, by using the dynamic game model, the game equilibrium result is that the scorched-earth tactics and the selling of crown-pearl by the target enterprises change the refined Nash equilibrium of the dynamic game, and make the acquirer give up the M & A. The influence of different strategies on the equilibrium results is further analyzed. Secondly, through the analysis of event study method, we can know that the short-term market reaction of Premium M & A is the best among the effective anti-m & A strategies of target enterprises, but the target company's management paid a high premium for the acquired company, which was not in line with its expected development potential, thus laying the groundwork for a subsequent plunge in its market price. While the act of amending the company's Articles of association effectively increases the difficulty for the acquirer to seize control, it also causes other investors in the investment market to question whether the management's power is too great to harm the interests of shareholders, affect the market price of the target enterprise.

 Finally, the three dimensions of Enlightenment, for the regulatory authorities to reduce the increase of investors on the shares of enterprises without actual control of the announcement line, and to strengthen the information disclosure system of corporate supervision. For the target enterprises, they should raise their awareness of the prevention of hostile mergers and acquisitions, select White Knights with the same goals and higher binding force in cooperation, improve the internal governance mechanism, and prevent management review from dereliction of duty, to protect the right to know of the minority shareholders in enterprises without real controllers, and to prevent the management from damaging the interests of investors for self-interest purposes.