Ward, 22, has been capped up to under-21 level with Wales and has previously been loaned by Liverpool to Morecambe.
He started his career with Wrexham, having a brief loan at Tamworth in 2011, before moving to Anfield the following the year.
"I am delighted to get Danny on board," Aberdeen manager Derek McInnes told his club website.
"He is a young goalkeeper we have been aware of for some time. We are thankful to Liverpool and [manager] Brendan [Rodgers] in particular for allowing this to happen.
"He is someone who is highly regarded at his club and they see the importance of getting him out on loan. Danny now has the task and challenge of playing football at a good level with us.
"We have real competition for places in all areas of the team, and we certainly now have that in the goalkeeping position."
Ward, who has made six senior appearances in his career, will be competing with Englishman Scott Brown, 30, and Scotsman Jamie Langfield, 35, for the Dons' goalkeeping position.
Aberdeen have signed goalkeeper Danny Ward from Liverpool on a season-long loan.