"The whole world benefits from a strong EU," he said in a speech to the European Parliament, a day after MEPs approved a landmark free trade deal between the EU and Canada.
"Canada knows that an effective European voice on the global stage isn't just preferable, it's essential," Trudeau told the assembly in Strasbourg, France.
Trudeau also hailed the 28-nation bloc as "a truly remarkable achievement and an unprecedented model for peaceful cooperation."
Opponents to the deal, known as CETA, slam the deal as a "Trojan horse" to big business and a danger to health, democracy and the rule of law.
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But Trudeau, speaking in a mix of French and English, said that the EU and Canada "have made a big step to deepen our relationship and increase commerce that is both free and progressive".
Trudeau spoke three days after meeting in Washington with US President Trump, who has vowed to embrace protectionism and reject big trade deals in order to preserve US jobs.
Trudeau said Trump expressed "a very strong focus on getting things done for those who supported him, believed in him."
The EU-Canada deal, known as CETA, could be an example for Trump, Trudeau said.
"Demonstrating that good relations with one's neighbours is a good way of getting things done, I think, that everyone is going to benefit from around the world," he told a press conference after his speech.
Trump has that Britain's vote to leave was a good idea and that other countries would likely follow suit.
He is also expected to nominate a pro-Brexit ambassador to the EU who believes that the bloc will disintegrate and that the euro single currency will fail.
In contrast, Canada moves closer to Europe with CETA.