First principle study with density functional theory was carried out to investigate the adsorption behavior of nitrogen oxide (NO and NO2) on pristine and B atom embedded gamma-graphyne including the adsorption energy, electron transfer, adsorption distance, magnetic moment, band structure, density of states and optical properties. The results indicate that C atom of sp(2) hybridization (compared to sp hybridization) is easier to be substituted by B atom with endothermic process. B atom embedded gamma-graphyne have notably stronger chemical interactions with NO and NO2 compared to pristine gamma-graphyne with larger adsorption energy and greater changes of molecule orbitals. The calculations of optical properties reveal that B atom embedded gamma-graphyne has more obvious changes of dielectric function after adsorbed NO or NO2 near 1.5 eV compared to pristine gamma-graphyne illustrating that B-graphyne has the prospect to detect nitrogen oxide using not only electrochemical method but also optical method.