Abstract: There isn’t a consistent conclusion about whether transnational technology M&As in China can improve technological performance. This article’s aim is to test and verify that absorptive capacity is crucial to corporations’ technological performance increasing. First, we built an evolutional game theory model based on a situation when M&A corporations and target corporations share tacit knowledge, in which dynamically evolutionary strategies are “contribute-contribute” and “not contribute-not contribute”. The game theory analysis manifests that absorptive capacity is crucial to the equilibrium of the evolutional game theory model which leads to an hypothesis that the better absorptive capacity a corporation embraces, the better technological performance it will gain after multinational technology M&As. Then we used data of quoted public companies from 2004 to 2009 as samples to build a Poisson regression model to do experimental test and the result is accorded with the hypothesis. This result depicts the mechanism of tacit knowledge sharing after M&As and proves that absorptive capacity is the key to increasing technological performance when corporations in China conducting transnational technology M&As.