In this paper, an ion chromatog. coupled with triple quadrupole mass spectrometry method was developed for 10 oligosaccharides, including mannuronic acid (M) and guluronic acid (G). Optimized ion chromatog. conditions: Thermo Scientific Dionex IonPacTM AS19-4 μm (2 mm × 250 mm, Anal.), 200 mmol·L-1 sodium hydroxide-water as eluent, flow rate 0.3 L·min-1, column temperature 30°C, conductivity detector connected to the back External pump, add 0.25 mL·min-1 acetonitrile. The ESI source was used, and the scanning method was selective reaction detection (SRM). The results show that: ion chromatog. had good retention and separation effects on mannuronic acid and guluronic acid with different ds.p., triple quadrupole mass spectrometry has excellent sensitivity and high selectivity compared with traditional detection methods; continuous in 5 injections, the RSDs were all less than 6.08%. The calibration curve has a good linear relationship, R2≥0.9990; the detection limit of the method is 0.34 μg·L-1; the detection results are accurate, and the recovery of the low, middle and high levels of the standard is greater than or equal to 90.2, so this method can be used for the qual. anal. of oligosaccharides and quant. anal.