Abstract: Paralytic shellfish poisoning is one of the most widely distributed and harmful biological toxins of red tide in the world, and the main toxin is saxitoxin. In this study, a kind of colloidal gold rapid test strip for detection of saxitoxin was tested in practice. According to the test, the test strip could be universally applied in sheDfish! and the detection limit of saxitoxin was 500 ugkg. Meanwhile, the test results of saxitoxin in 30 samples of different shellfish were completely consistent with that of liquid chromatography - tandem mass spectrometry. It took about 20 minutes to test a single sample. The results showed that the test strip had high sensitivity and specificity, convenient operation, stability and reliability, which could meet the needs of on - site detection. It was available for the grass - roots fishery regulatory department to carry out the rapid detection and screening of paralytic shellfish poisoning, which was of great significance for strengthening the ability to prevent and control the quality and safety risks of shellfish during the red tide.