Fifty firefighters are currently tackling the blaze, which was discovered in the early hours and led to the evacuation of the station.
Trains will not be stopping at the station 'until further notice', a spokesman for East Midlands Trains said.
Nottinghamshire Fire and Rescue Service tweeted: "There are now 10 fire engines in attendance approximately 50 firefighters fighting the fire at the Nottingham Train Station".
Nottinghamshire Police said surrounding roads are closed.
The force tweeted: "Transport in the area will be severely disrupted."
A spokeswoman for East Midlands Ambulance Service said: "We have a clinical manager and specialist paramedics at the scene."