The robbery happened on Wednesday as the team member, who was not a high-ranking employee, was in a car taking him to his hotel from the airport and both he and his driver had watches and wallets taken.
Nobody was injured in the incident and the team member remained in Mexico for the race at the Hermanos Rodriguez circuit. His name was not released.
Street robberies are commonplace in Mexico and also at the next race in Brazil, where team employees have been held up at gunpoint in the past as they travelled to and from the Interlagos circuit.
McLaren's Jenson Button was the victim of an attempted armed robbery in 2010, the year after he won the title, but his police driver smashed his way through traffic to escape when the gunmen were seen approaching.
Sunday's race in Mexico could be a title decider with Mercedes driver Nico Rosberg 26 points clear of triple world champion team mate Lewis Hamilton with three races remaining.
Mercedes have already clinched their third successive constructors' title.
(Reporting by Alan Baldwin; Editing by Clare Fallon)
