who can tell me the most excellent university in canada?

It depends on which field/sector you are pursuing. If you are talking Finance, the University of Toronto must be the BEST. Its finance ranks no.7 among the world according to the Financial Time. Investment banking recruiters look at the Financial Time as reference.

" Best in finance **

1 University of Chicago GSB

2 New York University: Stern

3 University of Pennsylvania: Wharton

4 Columbia Business School

5 University of Rochester: Simon

6 London Business School

7 University of Toronto: Rotman

8 Rice University: Jones

9 MIT: Sloan

10 Coppead "

Referenece:
http://media.ft.com/cms/16dc8c40-afc7-11db-94ab-0000779e2340,dwp_uuid=991cbd66-9258-11da-977b-0000779e2340.html
http://rankings.ft.com/rankings/mba/rankings.html

Based on the latest ranking, Rotman is the best among all the other Canadian business schools.
I've answered a lot of questions about Canadian business schools, you can feel free to look at some of mine in order to give you some insight.

ex.
http://hk.knowledge.yahoo.com/question/?qid=7006100400352

University of Toronto - Rotman
Western Ontario - Ivey
York University - Schulich
Queen's University
UBC
McGill

Hope it helps. Good luck!