chengdu123, for federal purposes you are a resident and therefore foreign earned income exclusion applies as long as you have a foreign tax home and foreign earned incoem.

The state issue is diferent -- as a resident of USA you must have  residency somewhere  ( in my old foreign assignment days I  knew a lot  of people establish  residency in states  with no  income tax  -- a PO box and driver's license). However there are lot of ExPats  that do not have any connection with any state.   States generally find this a lucrative tax item -- because the  earnings are often high and  therefore many  states do not recognize the  exclusion.  However, absent any specific directive from your home state, as a US resident alien and with no in-state sourced income, there is not much your state can do to require a filing.  This is true especially if you do not intend to come back to your home state.  If you are not a resident of a state  they cannot tax your world income , just in-state sourced income.  I would suspect though that if you have previously filed MA returns  and now don't , they will send you a notice  of non-filing. All you have to do is tell them that you do not live in the state anymore -- this will mean you will lose your driver's  license and when you come back have to take the written test again.  That is my view.