With　societal　and　economic　development,　ammonia　has　become　an　important　product　in　the　chemical　industry,　gaining　increased　importance　among　energy　sources　as　a　carrier　for　hydrogen　storage　and　transportation.　As　liquid　ammonia　transportation　through　pipelines　generally　occurs　at　medium　to　low　pressures,　the　leakage　process　involves　complex　jet　evaporation.　In　this　study,　the　temporal　changes　in　a　vertically　leaking　liquid　ammonia　solution　were　simulated　and　the　variations　in　velocity,　temperature,　and　concentration　fields　in　the　near-field　region　of　the　liquid　ammonia　leakage　were　analyzed.　The　results　show　that　when　liquid　ammonia　leaks　under　2　MPa　and　20　°C　from　a　20　mm　leakage　hole　to　a　25　°C　atmosphere,　an　ammonia　cloud　core　forms　at　17.54　m　from　the　leakage　hole　in　1　s.　By　analyzing　the　changes　in　ammonia　velocity,　concentration,　and　temperature　during　the　process,　the　leakage　process　of　liquid　ammonia　can　be　divided　into　four　stages:　the　initial　leakage,　air　entrainment,　cloud　formation,　and　cloud　dispersion　stages.　The　liquid　ammonia　leakage　process　is　more　sensitive　to　changes　in　pore　size　and　has　a　greater　impact　on　the　shape　of　the　ammonia　cloud.　Pressure　has　a　weaker　effect　on　the　leakage　process　and　mainly　affects　the　liquid　ammonia　jet　velocity　during　the　initial　leakage　stage.　©　2025　Author(s).