Sharapova, beaten by Serena Williams in last year's final at Melbourne Park, broke Jankovic at her first opportunity and never looked in trouble against the third-seeded Serb, who received treatment for a lower back injury during the match. Sharapova raced out to a 5-0 lead but suffered an attack of nerves when serving for the first set, allowing Jankovic to reel off three successive games before she finally sealed it on her sixth set point.
"I was up 5-0 and playing too good for my own level," Sharapova said in a courtside interview. "I was playing solid tennis and doing all the right things but I let it slip.
"Jelena plays really good tennis when she's behind so I'm really happy to be back in the final. I'm happy I've been able to play some good tennis."
Jankovic, plagued by shoulder and leg injuries throughout the tournament, lost her first service game in the second set before leaving the court to receive treatment on a lower back injury.
She returned and held serve in the fifth game but could not match the power of Sharapova, who sealed victory when a Jankovic backhand sailed wide.
The 20-year-old Sharapova, a former Wimbledon and U.S. Open champion, will play either fourth seed Ana Ivanovic or ninth seed Daniela Hantuchova in the final.
"I'll have a peek at their match but I won't sit and watch it," said Sharapova.
"I'm just looking forward to being the final again and whoever it is I hope I can produce some good tennis."