The 3.7-mile circuit is being built within the complex that will be used for the 2014 Winter Olympics.
It scheduled to host the first ever Russian Grand Prix next year.
Ecclestone visited the site alongside Russia's deputy primer minister Dmitry Kozak and members of the organising Formula Sochi team.
"I was here even before building works started and was impressed. Now I'm happy with how things are going on," said Ecclestone.
Ecclestone later met with Russian president Vladimir Putin.