You can change to H1B status in U.S. So you don't have to go outside to get H1B visa.
If you already have H1B, and want to go to China for a visit, You have to apply H1B visa to come back. You can't get h1B visa in U.S.
If you have Canadian Passport, it MAY be easier, but I am not sure. Usually it is easier to get H1B visa even for Chinese Passport Holder, because Visa Officer can't use 移民傾向to reject your application. But now a days, many people get Background Check, which may take a couple of months. If you get Background Check, even you have Canaidan Passport, it won't help.
If you already have H1B, and want to go to China for a visit, You have to apply H1B visa to come back. You can't get h1B visa in U.S.
If you have Canadian Passport, it MAY be easier, but I am not sure. Usually it is easier to get H1B visa even for Chinese Passport Holder, because Visa Officer can't use 移民傾向to reject your application. But now a days, many people get Background Check, which may take a couple of months. If you get Background Check, even you have Canaidan Passport, it won't help.
