Mr. Chan had held the post for nearly five years and oversaw an expansion that took Wal-Mart to 353 China stores from about 70 in 2006. He couldn't be reached for comment.

Wal-Mart also announced the resignation of Clara Wong, its senior vice president for human resources in China. She also couldn't be reached.

The division already had gone through management turmoil. Roland Lawrence, Wal-Mart's chief financial officer for China, and Rob Cissell, its chief operating officer in the country, resigned in May. Wal-Mart cited personal reasons for their departures, as well.