Lambert, 24, allegedly produced numerous videos between October and November 2010 and sent McAdoo those videos while he was stationed abroad, prosecutors said.
Court documents say the girlfriend even streamed live images of herself sexually abusing minors whom she was babysitting.
McAdoo, 31, was interviewed in Afghanistan and then returned to Camp Pendleton last week.
On Thursday, Jan. 27, he was arrested at the base on federal charges and transported to a San Diego jail cell.
He faces two counts of receiving the child porn and could face more charges once he's transported to Oregon.
Lambert was charged for sodomy, sex abuse and using a child in a display of sexually explicit conduct according to a Portland television station.
She pleaded not guilty to all counts on Wednesday and is being held on $5.25 million bail, the station reported.