The blaze was reported shortly after 5:30 on the right shoulder of the eastbound side of the freeway, according to a California Highway Patrol incident log.
Firefighters responded and extinguished the flames, which burned out more than half of the bus. The vehicle's origin and intended destination were not immediately confirmed.
One person was pronounced dead at the scene.
Several lanes remained closed as of 8 a.m., and eastbound traffic was heavily backed up as commuters slowly made their way past the crash site.
The cause of the fire was under investigation.