Picard had a goal and two assists to help Canada improve to 2-0 at the tournament. Seven different players scored for the two-time defending champions.
"Today all four lines played excellent," said head coach Laura Schuler. "In the past we've had goals coming from one or two lines and today it was all four really contributing. So I was really proud of that."
Sarah Potomak opened the scoring at 5:03 on the power play and Stephanie Lalancette made it a two-goal game at 10:53.
Canada piled on in the second period as Picard, Victoria Bach, Jessica Healey, Rebecca Leslie and Alexandra Labelle padded the lead. Finnish netminder Anni Keisala stopped 52 of 59 shots.
Canada opened the tournament with a 7-1 rout of Japan. Canada has an off-day before resuming preliminary-round action Wednesday against the Czech Republic.
"I think we've done really well," said captain Lauren Wildfang. "We've worked really hard to get where we are and I think that just needs to continue."
The Czechs also improved to 2-0 with a 3-1 victory over Japan. The game against Canada will be for the top seed in Group A.
Later in the day, Russia defeated Sweden 5-1 and the United States dumped host Hungary 7-0.