I need to go to macau but transit through shanghai, do i need visa? can i obtian it within one day?

Therry, if you stop over in Shanghai for less than 24 hours, then you don't need it. If the layover is longer, you need to get one in advance. Genrally speaking, you can obtain the transit permit within four working days, but even if you use urgent service, it's likely that you have to wait for two or three working days.