The Cheetahs ran in six tries through Neill Jordaan, Ryno Benjamin, Clayton Blommetjies and a hat-trick from Sergeal Petersen to run out 55-17 winners after leading 26-0 at half time.
The Lions suffered another blow after losing Julian Redelinghuys to injury.
The Springbok prop dislocated his neck at the C5/6 level. He spent the night in traction at a Bloemfontein hospital and is set to have surgery on Sunday.
Over in Pretoria, the Bulls left it late, but were able to beat Western Province 36-30 to book their spot in the final.
Replacement scrumhalf Ivan van Zyl scored a try in the 78th minute to see his team over the line in front of their home fans.
It is the Bulls’ first final since 2009.
The final, at Free State Stadium, kicks off at 16:00pm on Saturday.
