Two crews from Huntingdon and the north roaming fire engine were called at 2.10pm today (Wednesday).
Firefighters are currently tackling the blaze and it is not yet known what time the road will reopen.
Cambridgeshire police have asked drivers to take alternative routes
Cambridgeshire police tweeted: “Due to a lorry fire the A141 is closed between the Wyton roundabout and the B1090 roundabout. Please avoid the area.”