The green, white, and red stand for Islam, peace, and courage, respectively. The red emblem in the middle stylizes the word 'Allah' (God) and also resembles a tulip, which symbolizes martyrdom.

If you look closely at the top and bottom of the white band, there's writing. The phrase 'God is the greatest' is repeated 22 times, commemorating the date of the successful Iranian Islamic Revolution in 1979 (the 22nd day of the 11th month in the Iranian calendar).