Objective: The efficacy of the Durio zibethinus cortex extract as spermicidal agent was investigated on mice sperms and human sperms. The intense color spoiled the final product appearance. The purpose of this study was to determine the effect of decolorization and the best formula for preparation the spermicide gel from D. zibethinus cortex extract. Methods: The extract of the D. zibethinus cortex was prepared by two-step methods before made into the spermicide gels preparation. First, decolorization used activated carbon and second, the extract was formed into solid dispersion with variation of the polyethylene glycol (PEG) 6000 concentration were 2%, 4%, 6%, and 10%. The extract quality was investigated by total phenolic. The gel preparation was evaluated for pH value, viscosity, and spreadability. Results: The decolorization reduced 23.25% of total phenolic. The variation of the PEG 6000 concentration increased the viscosity (p<0.05) but decreased pH value and the spreadability (p<0.05). Conclusion: The decolorization increased final product appearance and formulation with 2% of PEG 6000 was found to be the best. Keywords: Spermicide gels, Durio zibethinus, Decolorization, Solid dispersion.