A first-half free-kick from Josh Harrop was added to by second-half goals from Sean Maguire and a wonder strike from Alan Browne.
Preston started well and top scorer Jordan Hugill forced a fine save from Neil Etheridge when he drove a left-footed shot across the keeper on 11 minutes.
The hosts were piling huge amounts of pressure on Cardiff and referee Oliver Langford twice turned down penalty appeals in a matter of seconds on the half hour.
Joe Ralls had Cardiff’s first effort on goal on 32 minutes and Preston were relieved after his deflected strike looped over Chris Maxwell’s goal for a corner, which came to nothing.
Preston continued to knock on the door as Ben Davies’ header from Harrop’s corner on 36 minutes flashed narrowly wide and they got their reward on 38 minutes, as Harrop’s free-kick from 26 yards evaded everyone and nestled into Etheridge’s bottom left corner.
North End were flying; minutes later, Maguire flung himself at Josh Earl’s cross but could only direct his effort straight at Etheridge who gathered at the second attempt.
Preston continued where they left off after the break, with Darnell Fisher shooting straight at Etheridge with the goal at his mercy on 53 minutes.
Cardiff boss Neil Warnock made two changes on 63 minutes to freshen his side up. The on-loan Liam Feeney replaced the anonymous Junior Hoilett and Lee Tomlin took the place of Loic Damour.
But it was to no avail as, on 70 minutes, North End doubled their lead when Maguire squeezed the ball between keeper and post for his second league goal of the season.
It had looked as though the summer signing – who scored his first English league goal on Saturday – had missed his chance to shoot but he finished past Etheridge to ease Preston’s nerves.
It was game over with Browne’s wonder goal on 78 minutes as the combative midfielder struck the ball sweetly from 50 yards out after Etheridge’s poor clearance.
The Deepdale crowd rose in expectation as the Cardiff stopper backtracked but failed to delay the inevitable and tipped the ball into the net.