A laboratory experiment with orthogonal design was conducted to study the effects of factors salinity, temperature, and light intensity on the growth and toxin production of Chattonella marina. Three levels of salinity (22, 33, and 45), temperature (20 degrees C, 25 degrees C, and 30 degrees C) and light intensity (2000, 3000, and 4500 lx) were installed. In all treatments, the three factors had no significant effects on the growth of C. marina, but salinity significantly affected the toxin production of C. marina. Under salinity 45, temperature 30 degrees C and light intensity 2000 lx, C. marina had the maximal growth rate; under salinity 22, temperature 20 degrees C and light intensity 4500 lx, the toxin production of C. marina was the maximal. Low salinity was not favorable to the C. marina growth but favorable to its haemolytic toxin production. When the growth of C. marina was limited, its haemolytic toxin production increased.