[Aim] This study investigated how allelochemicals extracted from the invasive plant Mikania micrantha affected soil nitrogen mineralization and how self-interested allelopathy may occur. Our aim is to provide new experimental evidence for the promotion of M. micrantha growth and its ability to repel native plants by releasing allelochemicals, thus providing insights into the invasive mechanism of M. micrantha.[Method] We conducted a classical bioassay for allelopathic experiments, the exogenous addition of allelochemicals to soil and an outdooor pot experiment to compare the differences between the allelochemical effects of aqueous extracts and crude extracts of M. micrantha and its two native companion plants (Persicaria chinensis and P. scandens). The effects of water extract and crude extract addition on soil nitrogen mineralization were investigated by determining ammonium nitrogen (NH₄⁺-N) and nitrate nitrogen (NO₃^--N) concentrations, as well as the effects of aqueous extract addition on the growth of M. micrantha.[Result] The results showed that the M. micrantha aqueous extracts (0.025 g·mL^-1 DW) exhibited a strong allelopathic inhibition effect compared to the extract of its two native companion species (P. chinensis and P. scandens), and soil nitrate nitrogen (NO₃^--N) increased substantially after the addition of M. micrantha aqueous extract. By contrast, the allelopathic effect of M. micrantha crude extracts was weak and soil available nitrogen (NH₄⁺-N and NO₃^--N) decreased significantly after the addition of crude extracts of M. micrantha. In this context, aqueous extracts were further used to investigate the growth of M. micrantha through an ourtdoor pot experiment, and the results showed that, compared to that of the native species P. chinensis, the aqueous extracts of M. micrantha displayed significant and self-interested allelopathy. This may be related to the increased protease activity and available nitrogen in M. micrantha rhizosphere soil in the outdoor pot experiment with the aqueous extracts of M. micrantha.[Conclusion] M. micrantha can promote the production of available nitrogen through water-soluble allelochemicals to realize self-interested allelopathy.