Generally, a Canadian transit visa is required to transit through Canada. However, Canada does have visa-exempt conditions. If your destination is the United States, you do not need to apply for one if you meet the following conditions:
Chinese citizens traveling to or from the United States who need to transit through Canada do not need to apply for a visa if they meet all of the following conditions:
1. Hold a valid Chinese passport;
2. Hold a valid U.S. visa;
3. Travel on flights operated by Air Canada, Jazz Aviation LP, Cathay Pacific, China Airlines, Philippine Airlines, or Air China;
4. Transit through Vancouver International Airport or Lester B. Pearson International Airport (Toronto) (Terminal 1 only);
5. Depart from Beijing, Hong Kong, Shanghai, Guangzhou, Xiamen, Fuzhou, Chengdu, Shenyang, Harbin, Manila, or Taipei in Asia, and take a direct flight to Canada.
In addition to meeting the above conditions, Chinese citizens transiting through Canada must hold a confirmed, same-day onward flight ticket to the United States and depart Canada on the same day. They cannot temporarily stay or overnight in Canada; otherwise, they will no longer be eligible for the Canadian transit visa exemption policy and must be subject to inspection by the Canada Border Services Agency.
If you are flying back to China from the United States and need to transit through Canada, you may be exempt from a visa if you meet the following conditions:
1. Arrive in Canada on an approved direct flight from the United States and proceed directly to the Canada Border Services Agency for customs clearance or wait for your connecting flight in a designated visa-exempt transit area. (Passengers who need to leave the designated visa-exempt transit area must be subject to inspection by the Canada Border Services Agency.) Note: If a Chinese citizen arrives in Canada on a non-approved flight, they must apply for a transit visa.
2. Are not being deported by the U.S. government;
3. Hold a valid U.S. visa and will not overstay in the United States;
4. Hold valid travel documents if traveling to China or another third country;
5. Hold a flight ticket departing Canada on the same day (cannot stay or overnight in Canada).