诺贝尔经济学奖获得者、美国经济学家George Joseph Stigler曾说过，“在美国，没有一家大公司不是通过一定程度和某种形式的兼并和收购成长起来的，而几乎没有一家大公司是主要是依靠内部增长发展起来的。”从中我们不难发现，企业的并购已经成为了企业做大做强的重要手段。它可以有效地为企业优化资源配置、提升企业价值。 企业并购本质在于获取合并的协同效应价值，而日益活跃的换股并购也不例外。换股并购不需要支付现金，而是增发股票来取得目标企业的股份。于是，目标企业的股份的转换比例就意味着收购企业的主要成本。 本文首先定性分析企业合并所预期取得的协同效应价值，然后定量的分析其价值与换股的转换比例之间的数量关系，确定合适的换股比例以达到双赢。并结合优酷与土豆合并的典型案例，计算分析优酷网与土豆网合并所要求的最低协同价值收益。在规避了合并风险的同时，真正实现的协同价值大于最低要求时，优酷和土豆合并才是双赢。 The Nobel economics prize winner, economist George Joseph Stigler once said, “in the United States, there are little big companies who can grow up without any forms of mergers and acquisitions by a certain degrees, and there are almost no big corporations who can grow up only rely on their internal growth.” It is obviously that enterprise merger and acquisition has become an effective means of becoming bigger and stronger companies. Merger and acquisition can effectively optimize the allocation of resources for the enterprise, and enhance the enterprise value. Enterprise carrying out mergers and acquisitions is for the sake of synergy effects in companies, and the stock-for-stock M&A is without exception. The stock-for-stock M&A issues new stock shares to exchange the target enterprise shares instead of paying cash. Therefore, the exchange ratio for the target stock shares means the main cost of the M&A. This paper first qualitative analyzes that enterprise merger and acquisition expect to obtain the synergy effects value, and then quantitative analyze the relationship between its magnitude of value and the stock-for-stock exchange ratio, in order to determine the right exchange ratio to achieve a win-win. This paper combines with Youku and Tudou M&A case, calculates and analyzes their minimum synergy effects value.