This paper determined the lethal concentration （LC） and hemi-inhibition concentration （HIC） of inorganic element Cu2+, Zn2+,Se4+,Cd2 to the unicellular alga Platymonas helgolandica var. tsingtaoensis （cell density were 3.4× 10’cell/ ml ）, Phaeodaetylum iTnutum （cell density is 2. 7 × 106 cell/ml） Dicrateria zhan jiangensis Hu （cell density were 5. 6 × 106 cell/ml）, Paviova luther（cell density is 2. 7 × 106 cell/ml）. The culture condition: temperature was 25±2℃, pH 7. 9± 0. 1, salinity 31±1.0,natural sunlight for 5 days. The different species unicellular alga with different absorbability to these inorganic elements were analyzed by Scanning Electron Microscopy X-ray Energy Spectrum. This is the international cooperation program with Department of Biology, University of San Francisco, USA.
