Beijing hosted the first Formula E race in 2014, around the park used for the 2008 Summer Olympics, and Hong Kong has featured more recently.
Hong Kong will host a race on March 10 next year and Sanya on March 23.
"(Returning) to mainland China is an important step in a key territory for the series and a market that’s instrumental to the continued development and uptake of electric vehicles globally," said Formula E chief executive Alejandro Agag in a statement.
The opening race of the 2018-19 season will be in the Saudi Arabian capital Riyadh in December, the first Formula E race in the Middle East.
The current season ends in New York later this month.
(Reporting by Alan Baldwin; editing by David Stamp)
