Michael Jace just pled not guilty to murder ... in the shooting death of his wife, April.
Jace was arrested May 19 after he called 911 to report he had shot and killed his wife in their L.A. home. Their two young sons were home at the time.
Authorities haven't discussed motive ... but, as we previously reported, the couple had been fighting over money problems.
He's currently being held on $2 million bail ... and faces 50 years to life in state prison if convicted.