The Briton, a three-time winner on the Circuit Gilles Villeneuve, lapped the island track in one minute 15.610 seconds on a sunny morning on the banks of the St. Lawrence River.
Brazilian Felipe Massa was second quickest for Mercedes-powered Williams to split the two works team cars, with Formula One championship leader Nico Rosberg clocking the third best effort.
Mercedes, who have started every race from pole this season and also won them all with the last five ending in one-two formation, again looked dominant with Hamilton 0.476 faster than Massa.
Ferrari's Fernando Alonso, a winner in Canada in 2006, was fourth fastest while Daniel Ricciardo put Red Bull fifth on the timesheets.
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The Australian's team mate and quadruple world champion Sebastian Vettel, last year's winner, was only 10th.
The session was red flagged briefly when Mexican Esteban Gutierrez spun his Sauber into the wall while several other drivers had trouble on a slippery track.
(Editing by Alan Baldwin)
