Personal cheque is not recommended because it takes long time to be cleared at the Bank. Some personal cheques may need to be celared by the central accounting unit in the bank and Bank will charge your for the clearing. (more than wire tranfer cost) Bank draft is better than personal cheque in terms of clearing process, but still take longer than wire transfer.
Wire tranfer is a easy process. Go to your bank and ask for a wire tranfer form. All the required information is listed on the form. Your parents can get those information from the Bank at their side. When your parents want to exchange CAD$ to RMB, the exchange rate used is for 现汇. Wire tranfer normally cost your around $30 +- if your amount is below $10,000.
Westunion is fast and good for small amount tranfer.
Hope those information helps.