Air-dried rice seeds were irradiated with 400Mev/amu accelerated argon ion beam. The genetic effects of M2 quantitative characters were studied.The results showedthat the heritability (hb2 )of all studied characters changed with different absorbeddoses. The heritability (hb2 ) and G.C.V.of all studied traits were rather highin the M2 generation rice seeds treated with 40Ar ion beam in the dose range of 60-120Gy. The relative genetic advance of each trait varied greatly with various dose treatments. Every trait could gain considerable genetic advance within the range of its appropriate absorbed doses.