In this experiment, the productions of hemolytic substances of Phaeocystis globosa Scherffel at various stages of growth and under different nutrient-limited conditions in semi-continuous cultures were studied. The results showed that the hemolytic activity was highest in stationary phase, but did not decrease as cell entered into senescent phase; the hemolytic activity varied significantly among different treatments. Significantly higher hemolytic activities were detected in N- and Fe-limited cultures compared to those under non-limited conditions. However, hemolytic activity of culture under P-limited condition (N∶P=150∶1) was the lowest, only 87.5 HU, lower than those under the other conditions. The average hemolytic activities per cell of cultures under N- limited and Fe-limited conditions were significantly higher than those under other nutrient limitation and non-limited conditions, whereas there was only a few differences between other three treatments. These suggested that growth and toxicity of Phaeocystis globosa were regulated by different factors, and that the toxin production might be related to cellular physiological stress, regulated by the availability of nutrients in Phaeocystis globosa.