The 33-year-old, from Bolton, posted on Facebook that his car "lost control" due to a phenomenon called aquaplaning.
Khan, who visited the Black Country in May, is believed to have crashed his Mercedes S350 between J12, Cannock, and J13, Stafford.
Luckily, the former unified light-welterweight champion escaped without injury in what he described as a "scary experience".
Aquaplaning occurs when a layer of water builds upon between tyres and the road's surface.
In a post on his official Facebook page, published at 9am on Sunday, he said: "Thank Allah Everyone is safe. A scary Experience. car lost control on the Motorway #AQUAPLANE Smashing into the side of the motorway barrier felt like being hit with a combo!"
His car, which is believed to be worth around £90,000, sustained significant damage.
Khan posted a video showing both the front and rear bumpers of his vehicle crumpled while one wheel was missing a tyre.