A spokesman for Cambridgeshire police said: "We were called at just before 4pm today (1 March) to reports of a car on fire on the A47 between Eye Green and Thorney.
"The road has been closed while the fire service deal with the blaze."
There are no reports of injuries.
A spokesman for Cambridgeshire Fire and Rescue Service said: " Crews from Dogsthorpe and Stanground were called to a fire on Thorney Road in Eye at 3.47pm.
"Firefighters arrived to find a well-developed fire involving a car.
"A crew from Dogsthorpe is still at scene making sure the fire is fully out and the area is safe."