Highly-oriented　Cu2O　thin　films　were　prepared　by　low　temperature　thermal　oxidation　of　evaporated　Cu　thin　films.　The　films　were　doped　with　different　doses　of　nitrogen　by　ion　implantation.　An　absorption　peak　appears　below　the　absorption　edge　in　the　absorption　spectrum　of　highly　nitrogen　doped　Cu2O.　The　effect　of　nitrogen　doping　on　the　crystal　structure,　electronic　structure　and　optical　properties　of　Cu2O　were　investigated　systematically　by　first-principles　calculations.　The　calculation　results　indicate　that　an　intermediate　energy　band　exists　in　the　forbidden　gap　of　highly　nitrogen　doped　Cu2O.　The　electron　transition　from　the　valence　band　to　the　intermediate　band　is　consistent　with　the　absorption　peak　by　experimental　observation.　Experimental　and　computational　results　indicate　that　nitrogen　doped　Cu2O　could　be　a　suitable　absorbing　material　candidate　for　wide-spectrum　detectors　or　intermediate　band　solar　cells.　©　2014　Chinese　Institute　of　Electronics.