The British singer picked up the top artist prize and best album for her second record, 21, winning 12 awards in total from 18 nominations.
Adele’s awards were not presented during the live show and the singer wasn’t present at the event.
Other winners included Justin Bieber, Katy Perry, Taylor Swift and LMFAO, who picked up song of the year for their single Party Rock Anthem.
The US pop act also picked up five other awards at the MGM Grand Casino Hotel.
Rappers Wiz Khalifa, Lil Wayne and R&B singer Chris Brown won top new artist, male artist of the year and R&B artist of the year respectively.
Former American Idol winner Jordin Sparks and John Legend performed a tribute to Whitney Houston at the event.
A shirtless Chris Brown sang his dance single Turn Up The Music with BMX bikers doing stunts on stage.
Katy Perry, wearing a white dress, hung above the stage in a swing to sing her latest single Wide Awake.
Justin Bieber also sang his new track Boyfriend accompanied by dancers dressed as clowns and neon geisha girls.
Other performers included Kelly Clarkson, The Wanted, Carly Rae Jepsen, Usher, Carrie Underwood, Linkin Park and Nelly Furtado.
Taylor Swift was named Billboard woman of the year and picked up the award from New Girl TV star Zooey Deschanel and veteran artist Kris Kristofferson.
Bieber, 18, picked up the award for the most social artist, thanking his 22 million Twitter followers and 43 million Facebook fans, saying “the internet is where I got my start”.
Perry was given the spotlight award for being the only female artist in history to have five number one singles in America from one album.
Michael Jackson is the only artist to have received the award previously.