Yang Xiuzhu is accused of embezzling more than $40m (£26m) when working as a public official.
Ms Yang, 70, was detained in the United States in 2014 after she tried to enter the country using a fake Dutch passport.
She is a high-profile target in Chinese President Xi Jinping's crackdown on corruption.
Ms Yang handed herself over to Chinese authorities, according to China's government watchdog, the Central Commission for Discipline Inspection.
Chinese state media said Ms Yang wanted to return to China for medical treatment, after feeling she had not received adequate care in the American prison system.
