High Performance Liquid Chromatography with Fluorescence Detection (HPLC-FD) and Mass Spectrometry (MS)have been used to analyze the purified Gonyautoxin2, 3 (GTX2, 3) and Gonyautoxin 1, 4 (GTX1, 4), the compound in the family of toxins responsible for paralytic shellfish poisoning(PSP), from a strain of the dinoflagellate Alexandrium tamarense. The results showed that the retention time of the purified GTX2, 3 and the purified GTX1, 4 was the same as that of the standard GTX2, 3 and the standard GTX1, 4 by the HPLC method. Combining the purified GTX2,3 and the purified GTX1, 4 showed the typical poisoning symptom of PSP toxins by mouse bioassay, the author thought the purified toxins were GTX2, 3 and GTX1, 4. The positive ionization produced he typical [M+H]+ molecular ion of the purified GTX2, 3 and GTX1,4 (m/z 396 and 412), which was the same as that of the standard GTX2, 3 and the standard GTX1,4 by MS method. The fragment ions of the purified GTX2，3(m/z 378，316, 298) and the purified GTX1, 4(m/z 394, 332, 314), generated by Collision Induced Dissociations(CID) of their repective [M +H ]+ ions, were also identical to those obtained for the standard GTX2, 3 and the standard GTXl, 4. They were further confirmed that the purified toxins were GTX2. 3 and GTXI, 4. Of course, the Nuclear Magnetic Resonance (NR)and Infrared (IR) are needed to fully confirm the results.