After a comfortable first-half performance, Preston where hanging on to their lead at the end.
Michael Ricketts, the former England international, had a great effort after three minutes but his 20-yard right-foot shot hit the bar before going over for a goal-kick.
Patrick Agyemang drove in a 20-yard shot which was saved by Neil Alexander diving to his left.
Preston took the lead after 22 minutes when David Nugent hit a cross from the left and Chris Sedgwick slid the ball home from inside the six-yard area to add to the one he scored at Cardiff in October.
Glenn Loovens was booked for a foul on Agyemang after 25 minutes and then Ricketts was booked for a foul on Callum Davidson.
Preston made it 2-0 after 42 minutes as Agyemang scored his fourth of the season with a 20-yard right-foot shot following a Paul McKenna pass from the left.
Preston went in at the break with a comfortable two-goal lead but Nugent did not return at the start of the second half and was replaced by Jemal Johnson.
Loovens pulled a goal back when the ball rebounded back to him after 67 minutes and he hit a 15-yard shot that went in off the bar following a corner but it was not enough for the visitors.