<p>This study investigated the effects of combustion pressure on the combustion characteristics and exhaust emissions of a pure hydrogen gas turbine nozzle. The influence of pressure on flashback (FB) and lean blowout was assessed using stability maps. Result showed that the flame structure significantly changed with varying combustion pressure, as observed through direct flame photograph. When the FB was characterized at various combustion pressures, a model for predicting FB could be linearly characterized by adding a pressure variable, as opposed to using only the Damköhler number (<Emphasis Type="BoldItalic">Da</Emphasis>) and flame Péclet number (<Emphasis Type="BoldItalic">Pe</Emphasis>_<i>flame</i>) at atmospheric pressure. The nitrogen oxide (NOx) characteristics were investigated using the combustion pressure and residence time as variables. The effect of the residence time became increasingly pronounced with the increase in the combustion pressure, resulting in higher nitrogen oxide emissions.</p>