Abstract: The paralytic shellfish toxins was investigated in farming shellfish samples collected from the middle of Fujian sea-area from the year of 2017 to 2018 by high performance liquid chromatography-tandem mass spectrometry.The results showed that:PST was not detected in the shellfish samples collected in 2018;PST was detected in the 17 batch of shellfish samples collected in 2017,with dcSTX as the most predominant components.Besides,GTX1-5 and dcGTX2-3 could also be detected in the samples.STX was not detected in the samples.The outbreak of Gymnodinium catenatum in the middle of Fujian sea-area had a certain impact on the detection of PST in the shellfish samples from the same area,including a greater impact on the mussels than oysters;but there was no impact on Sinonovacula constricta and Ruditapes philippinarum.