The surface free energy properties of fluoro rubber（F_246G，F₂₄₆₃,F₂₃₁₁,F₂₃₁₄）and RDX were measured by inverse-gas-chromatography （IGC). Parameters of chromatic dispersion,acid property,base property of fluoro rubber and RDX were calculated by ten known acid,base and natural probe molecules. The results show that fluoro rubber is basic and RDX is acidic. Fluoro rubber and RDX have acid-base action.