The Gators (4-1) won their third straight, avenging a three-point, overtime loss to the Dolphins last season.
Florida built a 20-point halftime lead and did not slow down, getting 21 points from Erving Walker and 15 from Brad Beal.
The Gators played without starting forward Erik Murphy, who suffered a knee injury in practice Thursday.
Florida made 11-of-25 from 3-point range, outrebounded Jacksonville by 11 and turned the ball over only seven times.
Jacksonville (2-3) was led by Russell Powell with 15 points.