Michelle Lu was found with multiple stab wounds. She was pronounced dead at the scene.
The couple's adult son was at home at the time of the incident and found his father holding the hatchet, but did not see the crime.
Michelle Lu reportedly worked as a nanny six days a week and was only home on Sundays.
James Lu was arrested on suspicion of murder and is being held on $1 million bail.
Investigators believe the killing was the result of a domestic dispute, Lt. Dan Rosenberg told the Los Angeles Times.
City News Service contributed to this story.