Vandoorne, 30, a former Formula 1 driver, also helped Mercedes become constructors' world champions for the second consecutive year.
But the German manufacturer will leave the discipline next season.
The last race of the championship was won by the Swiss Edoardo Mortara (Venturi), who finished 3rd in the championship behind Vandoorne and the New Zealander Mitch Evans (Jaguar), the only one still able to challenge the title to the Belgian driver before this last round. .
"It's the best feeling. It's been a great season and the team has done a great job. Mitch and Edoardo have been pushing me all season but it's all been about consistency. They have more victories than me but I have more podiums", declared the Belgian pilot.
Although he has only won one event this season, in Monaco, Vandoorne has been very consistent, managing to score points in 15 of the 16 races and reaching the podium seven times.
He succeeds in the championship list to his Mercedes teammate, the Dutchman Nyck de Vries, forced to retire on Sunday.
The "Gen2" single-seaters will give way next year for the ninth year of this championship to the "Gen3".
They will be lighter and more powerful and will have more range than current single-seaters.
Mercedes, however, decided to withdraw from the discipline at the end of this season and sold its team to McLaren, another F1 player.
Maserati for its part has announced its arrival in Formula E next season alongside other major brands such as Porsche, Jaguar, Nissan and DS (PSA group).
Contested on urban circuits, Formula E is intended to be the counterpart of F1 but by running fully electric single-seaters while those of Formula 1 use hybrid thermal engines.
Frenchman Jean-Eric Vergne, double Formula E world champion in 2018 and 2019, only finished 4th in the championship this year and his DS-Techeetah team 3rd among manufacturers behind Mercedes and Venturi.
Born in Kortrijk, Stoffel Vandoorne has been racing in Formula E since 2019 and finished 2nd in the championship in 2020.
Champion in the GP2 category (now Formula 2) in 2015, he then joined the McLaren Formula 1 team.
But this was experiencing a slump at the time and Vandoorne could not do better than twice 16th in the championship in 2017 and 2018.
© 2022 AFP