Caquatto, 17, edged teammate Shawn Johnson, a 2008 Olympic gold medalist, 14.525 to 14.500.
The 17-year-old senior at Naperville Central High School won the individual all-around Wednesday and gold in the team event Monday.
The bars final was her last event of the Pan Am Games.
University of Illinois freshman C.J. Maestas took bronze in rings. Ohio State grad Brandon Wynn won the gold.