Abstract: By taking Isochrysis galbana powder as the raw material, the process optimization of extraction conditions with the organic solvent of fucoxanthin in Isochrysis galbana, the separation and purification by silica column chromatography, and the qualitative analysis by UPLC-GC-MS were studied in this paper. The process optimization parameters of extraction conditions were determined mainly by the methods of single factor test and orthogonal optimization, and then the fucoxanthin was separated and purified by silica column chromatography. Last, the fucoxanthin was quantitatively detected by UPLC and qualitatively analyzed by LCQ Fleet. The results showed that the optimum extraction process was as follows:the extraction temperature was 35℃, the solid-liquid ratio was 1:30(g/mL), the extraction time was 15 min, and the extraction times were twice. Under these conditions, the extraction rate of fucoxanthin reached 12.03 mg·g^-1, the optimal recovery rate was 86.35% and the purity was 29.78% after the separation and purification by silica column chromatography, and the mass fraction qualitatively analyzed by LCQ Fleet was 659.090 2. The results of this study provided a theoretical basis for the rapid industrial extraction of the active substance of fucoxanthin from Isochrysis galbana.