To investigate the effects of the biological nitrification inhibitor syringic acid (SA) on soil nitrification and nitrous oxide (N2O) emissions in different soils, three typical agricultural soils in China, namely calcareous soil, paddy soil, and yellow soil, were selected for incubation experiments. The effects of different concentrations of SA on the nitrification rate and N2O production in these three soils were studied, and the main factors regulating the effect of SA were explored. The results showed that SA had inhibitory effects on nitrification and N2O emissions in neutral paddy soil and acidic yellow soil, with inhibition rates of 20% to 55% and 11% to 60% on soil nitrification rate, and inhibition rates of 55% to 65% and 13% to 24% on N2O emissions, respectively. On alkaline soil, SA has no significant effect on nitrification rate and N2O emissions. The inhibition of soil nitrification by SA on yellow soil has a dose effect, but there is no dose effect on the reduction of N2O emissions. Through two factor analysis of variance, it was found that both soil type and SA concentration can affect the nitrification inhibition efficiency of SA, and the two have an interactive effect, but the latter has no significant impact on the emission reduction of soil N2O. The correlation heatmap analysis further indicates that soil pH, organic matter and clay content may be key factors affecting the nitrification inhibition and N2O emission reduction of SA soil. Soil conditions with slightly acidic and high organic matter and clay content are more conducive to the effectiveness of SA, which provides a theoretical basis for the precise application of BNIs.