A spokesman for the airline says the plane had not yet made it to the runway when a smoke indicator sounded.
Graeme Burns says the 72 passengers and four crew members walked off the plane back into the Ottawa airport lounge when the evacuation order was given.
He said Transport Canada officials were looking at the plane to determine the cause of the alarm.
The airline was scrambling to find alternate travel arrangements for the passengers, although it was unclear whether another plane would be available today.
There were reports of a burning odour on the plane but no visible signs of smoke and no injuries during the evacuation.