Abstract: Polyunsaturated fatty acid plays an important role in the physiological activity of human and animal. Marine microalga is rich in polyunsaturated fatty acid. This paper reviews the influence of environmental impact factor (temperature, light radiation, chemical composition of culture solution, ventilation volume, methods of storage and culture, and so on) on the content of PUFA in the marine microalgae, and the progress on the culture of marine microalgae by photo-bioreactor, to provide a theoretical reference for the follow-up research.