The synchronous fluorescence spectra of five phytoplankton species growing under three temperatures (25, 20 and 15 degrees C)and three illuminations (7000, 4100 and 1100 Lx)were measured and processed by multinomial smoothness and autoscaling to obtain the characteristic spectra. Principal component analysis was used to obtain standard spectra. The analysis shows that at different temperatures, the characteristic spectra of Skeletonema costatuma, Isochrysis galbana, and Platymonas helgolanidica show high similarities, while the spectra similarities of Alexandrium tamarense and Gymnodinium stein are not as good as the above three species. The standard spectrum of Skeletonema costatuma, which belongs to Bacillariophyta, is quite different from those of Alexandrium tamarense and Gymnodinium stein, which belong to Dinophyta.