I join a server that needs dig lots of iron ingot
but the command #set [mineScanDroppedItems] can't find iron ingot(the server can't drop raw iron
can someone help me?

There is no feature in Baritone that would allow you to automatically collect arbitrary drops while mining so if #mine with mineScanDroppedItems doesn't do it on it's own you will have to pick up the items yourself or find a different mod to do it for you (I don't know about any such mod).