Depends what method they used to ship your item. If it's a private courier like DHL, UPS, FedEx, then the Canadian branch of the same company handles it here. If they mailed it using China Post (which includes ordinary surface/air mail, registered mail, ePacket, EMS) then it will be handed off to Canada Post, usually in Vancouver.

You won't incur any extra shipping charges, but you may have to pay duty and/or PST/GST/HST on the item. If that's the case, the shipping company will pay the fees for you up front, then collect them you from on delivery, plus a brokerage fee for handling the Customs clearance and fees on your behalf.

ETA: If the item is being delivered by courier, you can account for your goods directly with CBSA and pay any required duties or taxes directly to them. It is a bit of a hassle and the courier companies don't make it easy, but you don't have to pay their (often absurd) brokerage fees that way.

http://forums.redflagdeals.com/way-avoid-outrageous-ups-fedex-brokerage-fees-1175703/
http://www.cbsa-asfc.gc.ca/import/courier/lvs-efv/prsn-eng.html

I don't _think_ you can do this for items arriving via Canada Post, but at least CP only charges you a flat fee of around $10 or so, and then only if there are fees due to CBSA on your item. Also, any package arriving by mail with a total value of 20 CAD or less gets a pass on duties & taxes.