Pfc Lynndie England, 22, entered her pleas on Monday at Fort Hood, Texas, to two counts of conspiracy to maltreat prisoners, four counts of maltreating prisoners and one count of committing an indecent act.
In exchange, prosecutors agreed to drop another count of committing an indecent act and one count of dereliction of duty.
If the plea agreement is accepted by the judge, Colonel James Pohl, a jury of officers and enlisted soldiers will decide her punishment following a sentencing hearing expected to last several days.
One of seven
The plea agreement, which came the day before England was scheduled to go to trial, lowers her maximum possible sentence from sixteen and a half years in prison to 11 years.
One of the ABC News photos that
made England a key abuse figure
England is one of seven members of the 372nd Military Police Company charged with humiliating and assaulting prisoners at Abu Ghraib in Iraq. She became a central figure in the scandal after photos of her surfaced.
One image showed her smiling and posing with nude prisoners stacked in a pyramid while giving a thumbs-up.
Another showed her holding a hooded, naked Iraqi prisoner on a leash, and one showed her smiling and pointing at a naked detainee's genitals while smoking a cigarette.
England's lawyers have argued that she and others in her unit were acting on orders from military intelligence to "soften up" prisoners for interrogations.
But army investigators testified during hearings last summer that England said the reservists took the photos while "they were joking around, having some fun".
The Abu Ghraib scandal, which went public in April 2004, damaged the image of America's military leadership at home and sparked outrage around the world.
Several government investigations have been conducted, but so far only low-level soldiers have been charged, although the defendants and other critics have alleged that high-level officials condoned the abuse.
England (L) may face a reduced
sentence thanks to a plea deal
Four other members of the 372nd and two low-level military intelligence officers have entered guilty pleas, with sentences ranging from no time to eight and a half years.
The only soldier to stand trial so far is Pvt Charles Graner Jr, the reputed ringleader of the abuses and said to be the father of England's infant son.
Spc Sabrina Harman, a former Abu Ghraib guard, is scheduled to go to trial at Fort Hood next week.