Abstract: Removal of phosphorus from synthetic wastewater by three species of green algae and one specie of bluegreen alga (Chlorella pyrenoidosa, Chlamydomonas mutabilis, Anabaena sp. and Scenedesmus bijuga) was investigated using calcium alginate embedded algae and also experiments on algae growth in synthetic wastewater were conducted. Results showed that high viability and a longer lag period were observed with immobilized cells than those with the suspending cells. The growth stabilities of immobilized Chlorella pyrenoidosa and Anabaena sp. were better than that of the others in synthetic wastewater. The removal efficiency of phosphorus by immobilized Chlorella pyrenoidosa, Chlamydomonas mutabilis, Anabaena sp. and Scenedesmus bijuga which was 39.8%, 28.3%, 33.0% and 30.7% respectively reached the maximum on the 3th day. It was indicated that immobilization of Chlorella pyrenoidosa was an effective way to reduce phosphorus in wastewater treatment.