The 53-year-old Public Enemy rapper, real name William Jonathan Drayton, Jr., was taken into custody early Wednesday morning in Las Vegas.
He was charged with felony assault with a deadly weapon and misdemeanour domestic violence.
The Flavor of Love reality TV star is accused of pushing 39-year-old fiancée Elizabeth Trujillo to the ground and wielding knives while threatening her 17-year-old son during a heated family argument.
The dispute is believed to have started after Elizabeth accused Flav of cheating.
The rapper was taken into custody and released on $23,000 bail.
He has denied the claims.
The Associated Press reports Flav's attorney, Tony Abbatangelo, appeared in a Las Vegas court on Monday on behalf of the star.
Flav could face up to six years in prison if convicted of felony assault. He faces up to six months in jail on the domestic battery charge.
A hearing is scheduled for November 20.