The case had raised diplomatic and legal issues because Beijing insisted on holding the trial even though the crime happened in another country.
The Beijing No. 1 Intermediate Court ruled that Li Ang committed "intentional homicide" in the death of Amanda Zhao, Li's lawyer Zou Jiaming said.
The two were in a relationship and living together in Burnaby, B.C., where both were students.
Zhao was 21 and Li 18 at the time.
The life sentence ends a long process started in 2002 when Zhao's body was found stuffed in a suitcase.
In May 2003, the RCMP charged Li with second-degree murder, and in February 2004 the force confirmed that he was questioned by police in Beijing.
However, the matter became mired in jurisdictional issues between the B.C. and federal governments and the fact that there's no extradition treaty between Canada and China.
China eventually agreed to waive the death penalty.
A Canadian diplomat was in the court Thursday, but would not comment.
_ With files from The Canadian Press.