The eighth-seeded Barty outlasted Anisimova in a rollercoaster 6-7(4) 6-3 6-3 victory on Friday night (AEST) and will take on Czech teenager Marketa Vondrousova on Saturday night (LIVE, FREE and in HD on SBS and streamed live via SBS Sport / SBS On Demand).
American Anisimova, who had knocked out defending champion Simona Halep in the quarter-finals, produced a remarkale comeback from 5-0 down to take the opening set and then take a 3-0 lead in the second, only for the momentum to shift again in favour of the Australian.
Anisimova - the first player born in the 2000s to reach the semi-finals or quarter-finals at a grand slam - continued to show great fight to save five match points but Barty sealed the win on her sixth despite light rain.
"I fought my hardest, it's just incredible," said Barty, who is looking to become the first Australian to win the French Open since Margaret Court in 1973.
"I went away from what was working but I am proud of the way I fought and found a way back into that match. It was cold, windy, very tough for the both of us.
"It's incredible, it's an amazing journey that I've been on. I can't wait to see what happens."
Barty will face unseeded Czech Vondrousova on Saturday after she became the first teenager to reach a grand slam final for 10 years after defeating Johanna Konta 7-5 7-6(2).
The 19-year-old lost the first 10 points of the match on a rainy Court Simonne Mathieu but had more guile than her more powerful opponent in testing conditions.
Vondrousova will hope to go one stage further than Ana Ivanovic in 2007, the last teenager to reach the Roland Garros final, when she lost to Justine Henin.
Sydney-born Konta, bidding to become the first British woman to reach a grand slam final since 1977, will be disappointed after squandering leads in both sets.
The 28-year-old, who had never won a round at Roland Garros before this year, had three set points when she led 5-3 in the opener, but on first lashed an easy volley well over the baseline with the court at her mercy.
From that point on, Vondrousova began to use her splendid array of drop shots, lobs and superb anticipation to take charge, helped by regular errors off the Konta racket.
Vondrousova, who has won more matches then any other player on the WTA Tour since the Australian Open, will become the first Czech to win the French Open since Hana Mandlikova in 1981 if she overcomes fellow grand slam final debutant Barty on Saturday.
ADDITIONAL REPORTING: REUTERS
