Hi dear community, i want connect 7 arduinos with a Raspberry Pi 3 and my question is ¿Can i connect all arduinos by USB and send data by serial to Raspberry pi 3?
A Pi does not have enough USB ports 
You will need one or more powered USB hubs.
Aa sorry, yes I have a usb hub shield with 7 usb ports. But is possible read all Arduino a data with raspberry by serial??
I've not used a Pi. But basically you should get 7 serial ports when you hook up 7 Arduinos.
crisreorc:
Aa sorry, yes I have a usb hub shield with 7 usb ports. But is possible read all Arduino a data with raspberry by serial??
Yes