Ultraviolet-B (UV-B) radiation has significantly negative effect on cell survival rate (P < 0.01) and positive effect on astaxanthin accumulation (P < 0.01) of Haematococcus pluvialis. H. pluvialis accumulated 3.2 mg/g of astaxanthin when being exposed to 5 W/m(2) of UV-B for 60 min prior to 72 h of high light treatment, which was 122% higher than that of the control. This UV-B treatment also significantly stimulated lipid peroxidation and the value of malondialdehyde and glutathione peroxidase activities were 156 and 166% higher than those of control, respectively (P < 0.01).