In this study, a sustainable nitrogen fixation process was presented under atmospheric conditions and without introducing hydrogen or any catalyst. The novel in situ synthesis in this study used an advanced spray-type jet plasma, which significantly improved the fixation rate of nitrite, nitrate, and ammonium. Furthermore, the mechanism focusing on the co-synthesis of the abovementioned three nitrogen compounds was proposed based on the synergistic interactions between the gas-phase plasma and liquid surface dissociation.