Abstract: This study investigated the effect of salinity and illumination on the growth of Alexandrium tamarense. Batch cultures were treated at a combination of different levels of salinity (10、15、20、25、30、35 and 40) and illumination (3 000 lx、6 000 lx and 12 000 lx).The results showed that illumination influenced the growth of A. tamarense significantly (p 0.05), and the value of salinity also influenced the growth of A. tamarense significantly (p 0.01). However, their interaction was not significant (p 0.05). The A. tamarense under 6 000 lx displayed the highest cell density and the best condition of growth among all groups of illumination in any salinity level. Meanwhile, the A. tamarense in the salinity of 30 revealed the highest cell density and the best growth condition among the 7 salinity gradients in the condition of any illumination. Among them, the highest cell density of 65.93104 cell/mL was achieved with the illumination of 6 000 lx and the salinity of 30.Its corresponding maximum and average growth rates were 0.3679 and 0.1553, respectively.