First-half goals from Dean Windass and Fraizer Campbell gave the home side a comfortable lead, with substitute Andy Dawson sealing the win on 63 minutes with a curling free-kick.
Preston came close in the opening ten minutes as the ball came to Andy Carroll with space in the area, but hos curling effort was well turned away by keeper Boaz Myhill.
Hull opened the scoring on eleven minutes as Stephen McPhee slipped the ball through to Campbell who raced in on goal and struck a shot from 12 yards which keeper Andy Lonergan managed to parry, but only on to the head of Windass who managed to nod the looping ball into the back of the net from close range.
The home side were soon 2-0 up on 21 minutes, with Windass turning provider as he swung in a cross from the right, which fell to the feet of Campbell, who neatly turned and fired the ball into the bottom corner of the net from 18 yards.
Preston manager Paul Simpson made two changes at half-time in an attempt to spark a comeback from the visitors, with Darren Carter coming on for Chris Sedgwick and Patrick Agyemang replacing Carroll up front.
However, Hull went 3-0 up on 63 minutes as substitute Andy Dawson curled in a left-footed free-kick from just outside the box into the top right-hand corner of the net past Lonergan.
Substitute Jay Jay Okocha nearly had the Tigers 4-0 up in the latter stages of the game as the ball fell to the Nigerian on the edge of box, who struck a fizzing shot which keeper Lonergan did well to stretch to and turn around the post.