The responses of seed germination and seedling growth of rice (Oryza sativa cv. Yueza 223), wheat (Triticum aestivum cv. Gaoyun 5) and maize (Zea mays cv. Shangyu 2) to simulated acid rain were investigated by dipping seeds into solution of pH2.5, 4.5 and 5.6 made from mixtures of H2SO4 and HNO3, and into distilled water (control). Different pH (2. 5, 4.5, 5.6) simulated acid rain showed no effect on seed germination of rice and wheat, but significant inhibition effect was found in the germination of maize. Seedling growth of rice , wheat and maize was inhibited by simulated acid rain. Biomass and contents of chlorophyll and ca rotenoids decreased to some extent in all the three crop species grown under simulated aci d rain, whereas no obvious changes in Chl a/b was exhibited in these crops. There was little effect on Fv/Fm and photochemical quenching of chlorophyll fluorescence (qP) in leaves of maize grown at pH 4.5 or 5.6 of simulated acid rain, but nonphotochemical quenching of chlo rophyll fluorescence (NPQ) decreased markedly, revealing that non-radiation energy dissi pation in the antenna of photosystem II was possibly damaged under acid rain condition.