經美國到加拿大

If you are flying back to Canada via the States with your HKSAR Passport, you do need a transit visa. (Please refer to the website: http://hongkong.usconsulate.gov/niv_twov_iti_faq.html)

In your case, I'd suggest you to consult with the Canadian Consulate in Hong Kong, should be able to renew your passport in Hong Kong, instead of spending the extra time and money on the US transit visa application. (refer to this website:
http://geo.international.gc.ca/asia/hongkong/consulate/main-en.asp)

2007-12-16 10:56:50 補充：
if you do not have a valid US vistor's visa on your HKSAR passport, you will NOT be able to transit in USA, as they do required the HKSAR passport holders obtain the visitor's visa for enter (travel) or transit in the USA.

2007-12-16 10:58:51 補充：
honestly, please do NOT try to fly to the States with your HKSAR passport but without the visa, even though you are just transit but not visiting the States.

這個是可行的,首先是你于離港前住美國時是手持特區護照,而在美國轉機到加拿大時亦是持著同一本特區護照。