The 24-year old Olympic and world champion prevented US slider Chris Mazdze becoming the first American to win a World Cup title in 16 years.
Italy’s Dominik Fischnaller, who won the season opener in Lillehammer, completed the podium while British luger Adam Rosen finished 27th.
“I feel totally comfortable here in Whistler," said Loch.
"I’m very happy to win once more on this track and I’m happy to get back the yellow jersey for the lead in the overall World Cup.”
Loch now leads the overall rankings by 30 points ahead of German team-mate David Moeller, fourth in Whistler, and world junior champion, Italy's Dominik Fischnaller.
© Sportsbeat 2013