New Zealand, who led 12-0 at halftime, have now won four straight matches against Australia since the final of the Perth event.
Jorja Miller, Michaela Brake, Risi Pouri-Lane, Mahina Paul and Sarah Hirini were the try-scorers for the champions.
The Black Ferns Sevens had already wrapped up the overall league title after winning four of the six previous rounds, including the most recent in Singapore. New Zealand won the Cape Town, Vancouver, Hong Kong and Singapore rounds.
The top eight men's and women's teams in the standings after the Singapore event then qualified for the Los Angeles season finale.
Olympic champions New Zealand beat hosts the United States 34-7 in the semifinals.
Michaela Brake scored a hat-trick of tries for the Black Ferns Sevens against the US with Jorja Miller, Jazmin Felix-Hotham and Sarah Hirini the other players to dot down.
The Black Ferns Sevens had already wrapped up the overall league title after winning four of the six previous World Series events, including the last three in a row before Los Angeles. New Zealand won the Cape Town, Vancouver, Hong Kong and Singapore rounds.
The All Blacks Sevens were beaten 31-5 by South Africa in the men's semifinals and eventually finished third after overcoming Argentina 38-17 in the bronze medal playoff.
It's the New Zealand men's first podium finish this World Series season.
South Africa will play Spain in the men's final.
