The 18-time Olympic gold medalist and world record holder in the event clocked one minute, 56.11 seconds as he continues his preparations for an Olympic comeback next year in Rio de Janeiro, Brazil.
Chase Kalisz finished 1.01 seconds back in second while Dakota Hodgson was third in 1:59.09, three seconds slower than Phelps at the King County Aquatic Centre in Seattle, Washington.
Phelps was still well off his American record of 1:52.20 set in 2008. He set the world record of 1:51.51 a year later in Rome.
