Chasing an easy target of 113 runs, the Chennai achieved the victory by losing only one wicket with 31 balls remaining.
Parthiv Patil and Suresh Raina struck unbeaten fifties to take their team into the final of the IPL. They added 102 runs off 75 balls for an unbeaten second wicket partnership.
Patil made 51 with eight fours and Raina scored 55 off 34 balls with four sixes and as many fours.
Earlier, the Kings XI Punjab could not take the advantage of toss and were restricted by the Chennai Super Kings at 112 for eight in the allotted 20 overs.
Winning the toss and electing to bat, Punjab collapsed for 112 runs for the loss of eight wickets in the allotted 20 overs.
Their main scorers were Ramesh Powar (28 not out), Wilkin Mota (25) and opener Shaun Marsh (23).
At one stage, it was looking very difficult for Punjab to reach 100 runs but an eighth wicket partnership of 35 runs between Mota and Powar made it possible.
Main wicket-takers from Chennai were Manpreet Gony (2-14), Makhaya Ntini (2-23) and Albie Morkel (2-27) while Muttiah Muralitharan claimed one for 19.
Kings XI Punjab: Shaun Marsh, James Hopes, Kumar Sangakkara (wk), Yuvraj Singh (captain), Mahela Jayawardene, Irfan Pathan, Wilkin Mota, Piyush Chawla, Ramesh Powar, VRV Singh, Sreesanth.
Chennai Super Kings: Parthiv Patel (wk), S Vidyut, Suresh Raina, Mahendra Singh Dhoni (captain), Chamara Kapugedera, S Badrinath, Albie Morkel, Manpreet Gony, Laxmipathy Balaji, Muttiah Muralitharan, Makhaya Ntini.