Visa required, except for :
- holders of Hong Kong (SAR China) passports.
TWOV (Transit Without Visa):
- ONLY IF ALL CONDITIONS BELOW ARE MET-
Visa required, except for Nationals of China (People's Rep.)
holding confirmed onward tickets transiting For details, click here on
the same calendar day (SEE NOTE 43594) (SEE NOTE 43595) and:
- holding a valid US visa ; and
- traveling on a direct flight from Beijing, Shanghai, Hong
Kong, Guangzhou, Manila or Taipei and connecting on a flight
to the USA; or
- traveling from the USA.

NOTE 43594: Facility available if transiting through
Pearson International Airport (YYZ) AND arriving on
aircraft operated by Air Canada or Jazz Air (insertion of
SSR TWOV in PNR is required). Note: codeshare flight
numbers of these carriers operated by another carrier are
not included.
NOTE 43595: Facility available if transiting through
Vancouver International Airport (YVR) AND arriving on
aircraft operated by Air Canada or Jazz Air (insertion of
SSR TWOV in PNR is required), or Air China, Cathay Pacific,
China Airlines or Philippine Airlines. Note: codeshare
flight numbers of these carriers operated by another
carrier are not included.
- The YVR In-Transit Pre-Clearance Facility (ITPCF) which
handles international passengers travelling to USA, is open
from 04-20 hours; the YVR facility that processes
passengers arriving from USA and continuing internationally,
is open 24 hours.
The YYZ ITPCF, which handles international passengers
travelling to USA, is open from 04-21 hours; the YYZ
facility that processes passengers arriving from USA and
continuing internationally, is open 24 hours.
Additional Information:
- Visitors are required to hold proof of sufficient funds to
cover their stay and documents required for their next
destination.
Warning:
- Visitors not holding return/onward ticket could be refused
entry.

这是网上的规定。

一、中国公民前往或离开美国，如需过境加拿大，满足以下所有条件时无须办理过境签证：

　　(一)持有效中国护照；

　　(二)持有效美国签证；

　　(三)搭乘加拿大航空(Air Canada)、加拿大爵士乐航空(Jazz Aviation LP)、香港国泰航空(Cathay Pacific)、中华航空(China Airlines )、菲律宾航空(Philippine Airlines)、中国国际航空(Air China)的班机；

　　(四)从加拿大温哥华国际机场(Vancouver International Airport)或多伦多皮尔逊国际机场1号航站楼(Lester B. Pearson International Airport (Toronto) (Terminal 1 only))过境；

　　(五)必须从亚洲的北京、香港、上海、广州、马尼拉、台北出发，乘坐直达加拿大的航班。

　　二、前往美国旅客需注意

　　(一)除满足以上各项条件外，过境加拿大的中国公民须持有确认的、飞往美国的、同日离开加拿大的联程直航机票(不能在加拿大临时滞留或过夜)；

　　(二)在加拿大转机的乘客在美国过境预先清关设备工作时间内(during the hours of operation of the U.S. in-transit pre-clearance facility)抵达，可不办理过境签证。因此，旅客应仔细核对航班时间。

　　三、错过转机航班乘客需注意

　　如旅客因错过转机航班或航班延误，而美国过境预先清关设备关闭，则不再享受加拿大过境免签政策，须接受加边境服务局检查。

我买了同样航线的机票，几次致电国泰，发现他们的工作人员业务水平参差不齐，这个最基本的问题都回答不尽相同，后来终于在一位资深坐席员那里得到肯定答复，经停温哥华不许加拿大过境签证！

楼主求解救！我也是准备坐国泰去美国，求问亲身经历，到底需不需要加拿大过境签呢？无限感激啊！

不需要，只要不入境就不需要加拿大的签证。

去英国经停好像要签

谢谢二楼

还是问问吧！加航和美航不需要，因航空公司而异

没经停过加拿大，年头去美国经停过日本，不需要日本签证，加拿大也一样吧！实在没有签证的道理，搂住放心吧！

不入境应该不要的吧。