The £1billion stadium, which will have a capacity of 61,559, will be the biggest for any London team when it is finished this year.
It will also host NFL games from next season and kick-start a huge regeneration of the run-down Northumberland Park area.
The Mayor, accompanied by Spurs chairman Daniel Levy, NFL executive vice-president Mark Waller and Haringey council leader Claire Kober, was given a tour of the site. They also visited Percy House, a Grade II listed Georgian townhouse which is now home to the Tottenham Hotspur Foundation.
Mr Khan said: “I look forward to seeing Tottenham Hotspur’s hugely impressive new stadium join the line-up of world-class sports arenas in our great city.
“I welcome the commitment from Spurs in building not just a fantastic stadium for Premier League football and the NFL, but also leading the regeneration of this area of London and investing in local people.”