Abstract: Microemulsion encapsulating oligomeric procyanidins from lotus seepods ( LSOPC) was fabricated. Mastersizer 2000 was used to evaluate the particle size. And the stability of LSOPC microemulsion was investigated. The particle size of LSOPC microemulsion was ( 0.33 ± 0.02) μm, and LSOPC microemulsion was stable under low temperature condition.Low concentration Na Cl, glucose and sucrose had little impact on the stability of LSOPC microemulsion. K+, Mg²⁺, Cu²⁺, Al³⁺ had less effect.Ca²⁺, Fe²⁺, Zn²⁺, Fe³⁺ were found to affect the stability of microemulsion, and the particle size of microemulsions increased to different extents.The IC50 values of free radical DPPH scavenging activity of LSOPC microemulsion and LSOPC solution were ( 6.55 ± 0.04) , ( 7.33 ± 0.04) μg/m L respectively.Reduction ability of LSOPC microemulsion was better than LSOPC solution.The results indicated that the antioxidant activity of LSOPC microemulsion was much better than LSOPC solution.