Bayern who are chasing a remarkable 12th consecutive Bundesliga title establish a 2-0 lead inside the opening 10 minutes.
Dayot Upamecano headed the visitors into a fourth-minute lead before Kane doubled the lead five minutes later.
Kane added the third and fourth goals after half-time.
The former Tottenham forward has a remarkable 15 goals in 10 league Bundesliga appearances after his third hat-trick since joining Bayern in the summer.
After scoring three against Darmstadt last week, Kane has back-to-back hat-tricks in the Bundesliga.
Despite the big win Bayern are still second on the table two points behind leaders Bayer Leverkusen who won 3-2 at Hoffenheim.
Kane is enjoying a devastating burst of scoring form with his goals against Dortmund his 18th, 19th and 20th for club and country this season.
Seventeen of those have come in a Bayern shirt.
He has 10 goals in his past five appearances for Bayern and England.
