Is 5400BD per annum a good salary for a person working in Bahrain ?

With income 5400BD per annum, what kind of living can a family have in Bahrain ?
Will it me low standard or average or high standard of living  ?

I would say your standards of living will be low-to-average. Not average but not low either. Somewhere in the middle. This, of course, is heavily influenced by your lifestyle, where you live, how much you pay for accommodation and transport etc.