Westwood, who had one bogey against five birdies in Wednesday's opening round, is at 12-under 132 after 36 holes. He's built a 3-stroke lead over Carlos Del Moral, Peter Hanson and Lloyd Saltman.
Five players are tied at 8-under and three others, including first-round leader Magnus Carlsson, are at 7-under and five behind Westwood. Carlsson shot even-par 72 in the second round.
Westwood started on the second nine of the Bro Hof Slott Golf Club and posted birdies at the back-to-back par 5s at 12 and 13. He was still 2-under after six holes but had birdies on the last three holes of his first nine.
He had another back-to-back birdie run at 4 and 5 and finished with another at the ninth hole, another par 5.
Saltman posted a double eagle 2 at the 548-yard 12th hole. He had 237 yards left on his second shot. He chose a 3-iron and the ball landed about 7 feet from the hole and rolled in. He also had six birdies and a bogey to match Westwood's 64.
Hanson, who played with Westwood, had a double bogey, a bogey and seven birdies for a 4-under 68 Thursday while Del Moral had one bogey in a round of 5-under 67.
Swim Week Miami Beach 2014 [PHOTOS]