The singer, who has been recovering from a foot injury for most of the year, picked up the coveted Best Female Artist and Best Newcomer prizes, as well as Best Song for "Price Tag," her collaboration with rapper B.o.B.
In a post on her Twitter during the awards, she writes, "Wow wow wow! Im dancing around! BTDMA ive just won #bestnewcomer amd #bestfemale im so happpyyyy!!!! Thank you #heartbeats for your support."
Boy band JLS also won big, scooping Best Group and Best Video for "Eyes Wide Shut," at the event at London's Roundhouse venue.
Other winners at the ceremony included Bruno Mars, who was named Best International Artist, and Adele - she landed the Best Independent Artist Prize. Breakthrough Artist of the Year went to Ed Sheeran.