Police say an officer tried to stop the small truck from leaving the Alexandra dock near the Pointe à Callière Museum but the driver accelerated and attempted to drive off.
An officer fired a at least one shot at the car and hit the driver's upper body.
There were two passengers in the car during the incident.
A party boat cruise with about 200 people on board had recently docked.
The driver, 24, is in serious condition but authorities do not fear for his life. A police officer was treated for shock.
Provincial authorities are investigating the incident.