買賣加拿大的股票?

You can try the following two online trading,
DBS Vickers Online and E-Trade
Vickers Online was at first called TD Waterhouse Online, a online stock trading company of a Canadian Bank (TD Bank) so I'm pretty sure it should have one of the best infrastructure for Canadian stock trading in HK. And currently DBS Vickers (sub company of DBS Bank) bought the Asia business of TD Waterhouse Online.
http://www.dbsvickers.com/Pages/default.aspx
E-Trade is an US online securities also very popular in America. I'm pretty sure the infrastructure of trading Canadian stock is great but it is just a online trading broker and not back by any bank.
https://global.etrade.com/hk/en/home
Hope this help,
Cheers