Compared　to　domestic　mergers　and　acquisitions　(M&As),　the　implementation　of　cross-border　M&As　by　firms　faces　more　uncertainties,　and　the　risks　of　both　M&A　decisions　and　resource　integration　will　increase.　Using　a　sample　of　cross-border　M&As　from　2007　to　2020　in　Chinese　listed　companies,　this　paper　combines　normative　analysis　and　empirical　tests　to　investigate　the　relationship　between　cross-border　M&A　and　corporate　investment　efficiency.　It　further　explores　the　regulatory　mechanism　of　cross-border　M&A　on　corporate　investment　efficiency.　The　results　show　that　(1)　cross-border　M&As　do　not　enhance　the　investment　efficiency　of　Chinese　enterprises;　(2)　cross-border　M&As　do　not　impact　the　investment　efficiency　of　state-owned　enterprises　(SOEs)　but　exacerbate　the　inefficient　investment　of　non-state-owned　enterprises　(non-SOEs),　particularly　in　terms　of　over-investment.　Heterogeneity　tests　reveal　that　the　effect　of　cross-border　M&As　on　investment　efficiency　is　contingent　upon　various　factors,　including　the　type　of　property　rights,　financial　constraints,　and　equity　concentration　of　the　merging　companies.　Furthermore,　the　level　of　economic　development　and　governance　in　the　host　country　and　the　degree　of　interconnectivity　between　the　host　and　home　nations　also　exert　a　notable　influence.　©　The　Author(s)　2025.