Abstract: Taking the listed companies in China’s growth enterprise market (GEM) from 2011 to 2017 as the research sample, this paper takes "overseas technology M&A motivation - overseas technology M&A behavior - overseas technology M&A performance" as the research framework, and uses the PSM-DID model to explore the interaction among overseas technology mergers and acquisitions, technical knowledge similarity and innovation performance. The results show as follows: ① The innovation ability of acquirers has a positive and significant influence on the decision of overseas technology M&A. ②The degree of similarity of technical knowledge has a positive and significant impact on the decision-making of overseas technology M&A. ③ Overseas technology M&A have a positive and significant impact on the innovation of acquirers.④ The higher the degree of the similarity of technical knowledge, the greater the promotion effect of overseas technology M&A on the acquirers'' innovation. This paper has certain enlightenment and reference significance for the acquirer enterprises to make overseas M&A decisions, which is helpful for enterprises to make long-term development decisions reasonably according to their own conditions and reduce the risk of failure of technology integration after overseas technology M&A.