to LZ: use western union, you will receive local currency no matter what currency the sender uses.
to LS: yes, if you wire Canadian dollar in Canada back to China. Based on Chinese exchange policy, individual cannot withdraw foreign currency, so once the individual in China receives money from abroad, when he/she withdraw those money, it will always be transfered to RMB at the exchange rate in the day he/she takes the money, unles it is payable to a company, trust, or organization.