The pertraction effect of monocarboxylic acids by methyl silicone rubber (PDMS) and vinyl silicone rubber membrane (PVMS) were investigated. Relations between the organic structure parameters and pertraction effect were founded. The pertraction experiment demonstrated that PVMS membrane have good extraction effect on formic acid and acetic acid compared with PDMS membrane. The pertraction effect of monocarboxylic acids were analyzed by organic structure parameters and silicone rubber membrane structure. Results showed that with the increase of octanol-water partition coefficient (Kow or P), molecular molar volume (Vm) and molecular polarizability (a) that extraction rate of monocarboxylic acids increased; however, extraction rate decreased with the increase of mass intrinsic solubility(S). Pertraction experiments showed a significant correlation between extraction rate and log P(Ｒ2 was more than 0.96), as well as a correlation between extraction rate and Vm (Ｒ2 was more than 0.81). Dipole moment (u) does not have apparent regularity in this study.