Sanxan is a novel microbial polysaccharide approved by the Chinese government for use in the food industry. In this study, we evaluated the usability of sanxan as a drug carrier using riboflavin as a model drug. Sanxan microcapsules were prepared using an extrusion dripping method. The microcapsules were loaded with riboflavin and the release effect was evaluated by in vitro digestion. Microcapsules with a sphericity factor greater than 0.95 and regular appearance could be obtained when the concentration of sanxan was 0.4% and 0.06 M HCl was used as the fixing solution; the hardness of the microcapsules was 633.3 g and their elasticity was 0.44. In the simulated gastric fluid, 3.3% of riboflavin was released, while in the simulated intestinal fluid, this value was 47.4%; this happened when the loading ratio of riboflavin to sanxan in the microcapsules was 7 g g⁻¹. Scanning electron microscopy showed that the viscosity structure of sanxan was an important factor for the slow release of riboflavin. These results revealed that sanxan can be used as a new polysaccharide material for oral delivery.