Abstract: The static simulation test for synthetic wastewater purification was carried out by using Chlorella pyrenoidosa entrapped in calcium alginate, and influence of copper at different pH on the nitrogenremoval efficiencies of immobilized Chlorella pyrenoidosa for ammonia and nitric acidcontaining wastewater were also investigated. Test results showed that comparing without copper in wastewater, when copper was added，the NH+3N removal of immobilized Chlorella pyrenoidosa in 5 days at pH=4, 5, 6, 7, 8 was reduced 4.0%, 0.6%, 5.9%, 6.0% and 4.4% respectively, the NH+3N removal of suspended Chlorella pyrenoidosa was reduced 10.9%, 22.4%, 15.5%, 14.5%, 20.2% respectively; The NO-3N removal of immobilized Chlorella pyrenoidosa at pH=6, 7, 8 was reduced 4.1%, 2.8% and 4.2% respectively, but the NO-3N removal at pH=4, 5 was increased 0.8%, 0.2%, the NO-3N removal of suspended Chlorella pyrenoidosa was reduced 4.4%, 9.2%, 5.3%, 10.6%, 10.2% respectively. So copper has inhibited the nitrite uptake efficiency of Chlorella pyrenoidosa in free cells than the immobilized ones, and the treatment of immobilization to algae smoothed the disruption of copper.