N2O and NO are two important reactive nitrogen gases in the atmosphere, which have a strong influence on the global change and ecological environment. Soil is a significant source of N2O and NO and their production in soils involving both biotic and abiotic processes. This paper summarized six main mechanisms of N2O and/or NO production in soils, including autotrophic nitrification, heterotrophic nitrification, microbial denitrification, chemodenitrification, nitrifier denitrification and dissimilatory nitrate reduction to ammonium. Some of the previous research results were also discussed and the perspectives for further study were put forward.