Abstract: A review over a lot of scientific literatures summarizes the application of photocatalytic technique in inorganic nitrogenous compounds, and elaborates from the fwo respects the recent research progress of photocatalytic degradation of inorganic nitrogenous compounds (NOx, NO₃^-, NO₂^-) and the methods of increasing photocatalytic degradation efficiency (such as the modification of TiO₂ photocatalysts, the development of new photocatalysts and new photoreactors, the reaction mechanism of photocatalysis degradation of inorganic nitrogenous compounds). This paper also infroduces the measures of making the conversion rate of NOx up to 60%, NOT to 32%, and evenmaking 50% NOx turn to N₂.