Lee shot an 8-under 64 at the Wildfire Golf Club for a two-round total of 129.
Miyazato had to settle for second place despite a 67 that followed her first-round score of 63, the lowest 18-hole total of her professional career.
Stacy Lewis shot a 65 Friday and was alone in third at 134. Lewis, the reigning LPGA Tour player of the year, has a chance to take over the world No. 1 ranking with a win this week whole current No. 1 Yani Tseng finishes no better than third.
Tseng shot a 72 Friday and was tied for 60th.