Two people in a blue car pulled up to the man on Starkie Drive, Oldbury, and attacked him at around 6.30pm on Tuesday.
The men took the keys to his white Vauxhall Viva used them to drive off with the vehicle.
West Midlands Police is investigating but so far nobody has been arrested.
One of the attackers is described as being 6ft tall and wearing a balaclava.
Any information on the incident should be reported by calling 101 or Crimestoppers on 0800 555 111 quoting the reference number 20/1885335/21.