[Obejective] To study on the microwave extraction technology of polysaccharides from Sargassum thunbergii. [Method] Single factor test was used to determine the effects of various factors on extraction rate. And orthogonal test was used to select the optimum technology. After deproteinization and decoloration of polysaccharides in S. thunbergii, the main components were detected by infrared spectrum. [Result] The optimized process conditions were 8 min microwave time, 540 W microwave power, 1∶30 (g/ml) solid-liquid ratio, and 3 min ultrasonic time. And the extraction rate of polysaccharides by microwave extraction was 6.5%. According to the results of infrared spectrum, pyranose was the main component of polysaccharides in S. thunbergii. [Conclusion] The microwave extraction method of polysaccharides from S. thunbergii was feasible and simple with an ideal extraction rate. [Obejective] To study on the microwave extraction technology of polysaccharides from Sargassum thunbergii. [Method] Single factor test was used to determine the effects of various factors on extraction rate. And orthogonal test was used to select the optimum technology. After deproteinization and decoloration of the polysaccharides in S. thunbergii, the main components were detected by infrared spectrum. [Result] The optimized process conditions were 8 min microwave time, 540 W microwave power, 1:30 (g / ml) solid-liquid ratio, and 3 min Ultrasonic time. And the extraction rate of polysaccharides by microwave extraction was 6.5%. The microwave extraction method of polysaccharides from S. thunbergii was feasible and simple with an ideal extraction rate