Representative environmetal pollution research institutions, USEPA and OECD do eco-toxic level researches but researches on phytotoxicity of nanoparticles are rare. In this study of nanoparticles' effects on plants, It's possible to evaluate phytotoxicity of them. Effects of three types of nanoparticles (nano-TiO₂, AgNP, nano-ZnO) on seed germination and root growth of two higher plant species (Lycopersicon esculentum , Phaseolus vulgaris) were investigated. The concentration range was from 0 to 5000mg/kg. By considering agglomeration and formation of precipitates, a filter paper in a petri dish with distilled water were used. Seed germination was not affected except for the inhibition of nano-ZnO on Lycopersicon esculentum and Phaseolus vulgaris at high levels. Inhibition on root length appeared in the treatment of AgNP and nano-ZnO on Lycopersicon esculentum and nano-ZnO on Phaseolus vulgaris at high levels. Matured plants of Lycopersicon esculentum showed phytotoxicity of AgNP by low chlorophyll contents, higher superoxide dismutase activity and less fruit productivity, while nano-TiO2 only showed higher Superoxide dismutase activity in the highest (5000mg/kg) treatment.