When you land in Canada, they will ask you to sigh Medical Surveillance Undertaking, otherwise I guess they will not allow you enter Canada.

Your obligation is to report to Canadian disease control center. They will make an apointment for you. You need go there and take X-ray. After another 6 month, go there and have another check.

The purpose of that is to make sure you don't have any disease harmful to the public.

It is not a big deal. What you need to do is to give them a call and explain that you are going back to China and see how it goes.