An attempt to prepare a solid polymer electrolyte from jackfruit gum was made. Jackfruit gum (JG) was purified and subjected to epoxidation process. Lithium perchlorate (LiClO4) was dispersed in JG and epoxidized jackfruit gum (EJG). The structural characterizations were made through NMR spectroscopy and gel permeation chromatography. Ion conductivity and melting point of JG/LiClO4 and EJG/LiClO4 were measured. Obtained results indicated that epoxy group was introduced in JG and chain scission did not occur during the epoxidation. Ion conductivity of EJG/LiClO4 in epoxidized natural rubber matrix was about 100 times higher than that of JG/LiClO4 in epoxidized natural rubber matrix. EJG and LiClO4 formed a liquid crystal. These may suggest the strong interaction between epoxy group in EJG and LiClO4.