Tseng won her fourth tournament of the year Sunday, taking the Honda LPGA Thailand by five strokes. Wie was the runner-up.
The Thailand event was the opening entry on the 2011 LPGA schedule, but Tseng had already won the Taifong Ladies Open in her native Taiwan, the ISPS Handa Women's Australian Open and the ANZ RACV Ladies Masters, also in Australia.
That success pushed Tseng to a ranking points average of 11.16, well ahead of Jiyai Shin (9.89), who Tseng pushed out of the No. 1 spot last week. Shin had been on top of the rankings for the previous 15 weeks.
Wie's strong finish in Thailand allowed her to move from 11th to eighth in the rankings.
Suzann Pettersen (9.30) is again ranked third but Choi Na-yeon (9.19) finished one stroke ahead of Cristie Kerr (9.18) Sunday, which allowed Choi to take the No 4 spot and left Kerr fifth.
Ai Miyazato (8.65) and Kim In-kyung (7.56) keep the sixth and seventh spots, respectively. After Wie (6.95) is Ahn Sun-ju (6.67), who drops one place to ninth. Paula Creamer (6.43) is again 10th. Kim Song-hee (6.20) falls from ninth to 11th.