Yue Minji opened the scoring before Janine Beckie of Regina and Kadeisha Buchanan of Toronto tallied in the second half for Canada.
"That's as strong a performance as I've seen these players put in over a 60-minute period," said Canadian coach John Herdman. "It bodes well, I'm really happy. It showed some real resilience in coming back."
The teams split their two meetings last year. Canada holds the No. 9 position in the latest FIFA world rankings, eight spots ahead of South Korea.
No. 13 China, the tournament host, and No. 25 Mexico are the other teams in the round-robin tournament. Canada will play Mexico on Tuesday.
All four teams are preparing for this summer's FIFA Women's World Cup in Canada. China and Canada are in Group A, South Korea is in Group E and Mexico is in Group F.
Canada had an international record of four wins, five losses and two ties last year.