Wales made promising start but Canada secured four-try bonus and led 28-0 at half-time thanks to McKinley Hunt's double and scores by Alysha Corrigan and Asia Hogan-Rochester.
Welsh number eight Georgia Evans yellow-carded for a high tackle in 48th minute, followed by Taylor Perry and Brittany Kassil going over for Canada.
After heavy loss to Scotland in opening match, Wales were nilled and are set for a group-stage exit.
Canada, ranked second in the world, have shown their credentials as challengers for the trophy by cruising past Fiji and Wales.
Live Reporting
Canada weather Wales stormpublished at 12:52 BST 30 August
12:52 BST 30 August
HT: Canada 28-0 Wales
Philippa Tuttiett Former Wales international
The best teams, when they get that bit of momentum, they build on it and that's what Canada have done. Canada weathered the early storm and found a way.
You have to look at the numbers on these players' jerseys to know who are forwards and backs because they are so inter-changeable.
There are been some really good tries from Canada.
Wales started brightly but Canada showed why they are the second best side in the world with four tries, three of those coming in a brutal spell under five minutes.
Prop McKinley
Hunt grabbed two tries while wings Alysha
Corrigan and Asia
Hogan-Rochester also crossed.
Much to ponder for Wales at half-time as their World Cup dream appears to be vanishing.
Converted try - Canada 21-0 Walespublished at 30 mins
30 mins
McKinley Hunt (Sophie de Goede con)
Relentless from Canada with a second try in three minutes and a second score for powerful prop McKinley
Hunt which is again converted by lock Sophie de Goede.