Mutliboxing allowed?

one character do quest or dungeon,another stay in cities with auctionhouse,allowed?

No, this is not allowed. You can read the details here in the ToU:

The only exception is that you may have two characters of the same faction in any non-hostile city with an Auction House. This may not be used to gain an advantage in PvP situations.

This means the only time you are allowed to multibox is when both of the characters are in the same non-hostile city with an auction house.

OK, thank you for your explanation.

It’s of no other use. It’s just that when one character is doing quests in the field, the other can scan the auction house price data in the city at the same time, mainly to save a little time. After all, it takes half an hour to scan. Not allowed?