回複：有無近期加拿大登陸的朋友指點迷津，謝謝啦

You don't need to get new H-1B stamp to get back to US if you stay in Canada for less than 30 days. But you may schedule an appointment with US Consulate on the day after you get back to US without H-1B stamp in case you are denied by US border officer, so you can go to US Consolate for new H-1B stamp. I did in the same way for the landing in last April and was allowed to entered without new H-1B stamp.