The inactivation of chlorella was studied using a circular device of photocatalytic reaction with TiO2/foam nickel as catalysts. Parameters such as reactor configuration, reaction time and pH of chlorella affecting the degradation rate of chlorella were studied. The results showed that photocatalysis with TiO2/foam nickel was an effective process for the inactivation of chlorella. After photocatalytic reaction for 10h, the degradation rate was more than 97.75%. With reaction time increased, the removal of chlorella increased gradually.