Maclean struck his first goal of the season after 29 minutes to give the visitors the lead.
But in between Ranger's Stefan Moore struck the post, and in a late surge Hogan Ephraim drew a fine save from Cardiff keeper Ross Turnbull.
QPR manager John Gregory:
"We were second to the ball over the pitch.
"Cardiff have a wealth of experience and I have to say they were on the front foot throughout and played very well.
"Apart from a period at the start of the second half, Cardiff dominated the game and our performance was poor.
"Cardiff chased lost balls, harassed our players and worked harder than us. We looked timid and well below par."
QPR: Camp, Rehman, Curtis, Stewart, Mancienne, Moore (Ward 64), Bolder, Ephraim, Rowlands, Nardiello (Nygaard 64), Blackstock.
Subs Not Used: Cole, Bignot, Cullip.
Booked: Bolder, Rehman.
Cardiff: Turnbull, McNaughton (Gunter 40), Capaldi (Whittingham 49), Loovens, Johnson, Ledley, McPhail, Rae, Sinclair, MacLean (Feeney 90), Parry.
Subs Not Used: Oakes, Purse.
Booked: Ledley, Sinclair.
Goals: Parry 29, 59.
Att: 12,596 Ref: P Joslin (Nottinghamshire).