What is the procedures if I need to verify or approve a Death Certificate issue in Toronto?

You should first get the Death Certificate notarized by the notary public and then get it authenticated by the Authentication and Service of Documents Section in Toronto. Finally, go to the consulate general of PRC to get the certificate attested.
You should fill out the Application Form for Notarization and Authentication.
After you submit the application, usually, 4 working days are needed. It will cost CAD 30.
You need to bring those documents with you: the application form, the Death Certificate, your passport and copy of its data page, and your residence permit in Canada.