Total for how many months a green card holder can stay out of usa in one year, or in 5 years? so his naturalization process will

Seeking employment outside the U. S. often complicates lawful immigration status. The pull to remain outside the U. S. creates pressure to abandon as a matter of law, even if it is not your intention. You must maintain a permanent residence, complete annual tax returns, and demonstrate your intent to establish a permanent residence in the U. S. If you take a job outside the U. S. and live abroad, then seeking a re-entry permit 'may' make sense. However, it may also complicate matters. You want to avoid staying outside the U. S. for more than 180 days. You should not simply land in the U. S. and leave on an annual basis. In situations like this, a careful and thorough review with legal advice is strongly recommended. A competent and experienced immigration attorney may have to spend an hour to explain the law based upon your situation to your satisfaction. This is not the time to be stingy.

To preserve your naturalization requirement of residency you may not incur more than six months of absence from the U.S. on the same trip and I believe may not incur more than 900 days of absence for the entire duration of your naturalization tern. However, my question is this. If you consider yourself a U.S. Permanent Resident you have to meet the criteria of a permanent resident in the U.S. U.S. Congress never designated a U.S. Permanent Lawful Resident Card (green card) to be a convenience document in lieu of an entry visa to the U.S. just to come to the U.S. and go back to your home country for "some work" as you put it.

The previous answers raise several important concerns. You need to worry about qualifying for naturalization, but also about maintaining your permanent residence. Consult with an immigration lawyer before devising anything and before leaving the US.