The former Rangers defender has had very few chances at Liverpool and spent the second half of last season on loan at Blackpool.
"It's good to have another defender on board and certainly one of Danny's pedigree," said Robins manager Derek McInnes.
"We came up against him last season with Blackpool and I saw him playing for Rangers against my St Johnstone team before that.
"He's had a frustrating time at Liverpool with chances limited. We thank Brendan Rodgers and Liverpool for accommodating this move.
"He's now got a chance to impose himself on our team and show what he can do. We've a lot of games to play between now and January, and with the absence of Lewin and Stephen to injury, Danny's arrival is timely."