The incident happened while he was parked in a layby on the Knockbracken Road in the early hours of this morning.
Police said the attacker demanded money from the driver, hit him on the head and forced him into the boot of his car around 1.50 am
The masked thug then made of with a sum of money in a red Seat car which had a second male inside.
The driver was left badly shaken after the incident.
Detectives in Lisburn have asked anyone who noticed suspicious activity in the area to contact them on the 101 number..