I am now a freshman in stomatology department of medical college and immigrated to Canada. Can I go directly to college after immigrating there? Can I continue to study my original major?

Whether you are an immigrant or not, you should apply for a university according to your previous grades and language scores. Whether you can study in this bank depends on whether your level can meet the needs of Canadian universities. I suggest you come and study, because many medical courses in China are different from here, and the certificate must be based here. You may study for nothing when you come back from studying in China. If you say that you are a senior five, but you are only a freshman and don't care about starting a better career again, then don't waste it. And you are an immigrant, so don't worry too much about tuition. Much cheaper than international students.