A new silicone pervaporation membrane for the removal of one of trace organics, 1,2-dichlorethane from water has been developed using polydimethylsiloxane (PDMS) and oli- gomeric sklylstyrene as a crosslinking agent of PDMS. Optimal conditions for fabricating the best membrane were detemined from swelling measurements and pervaporation experiments and then the membrane was characterized at different membrane thickness and operating con- ditions. In the pervaporation separation of 55-70 ppm of 1,2-dichloroethane aqueous mixtures, the developed membrane has flux of 2.5-330 g/(m² h) and selectivity of 230-1750 depending on membrane thickness, permeate pressure and operating temperature. Water permeation through thin membrane was found to be subjected to significant desorption resistance, while the desorption resistance and thermodynamic factors as well as the concentration polarization of the organic at the boundary layer in feed can affect the organic permeation, depending on membrane thickness. Selectivity change with permeate pressure depends on membrane thick- ness : at small membrane thickness range, selectivity increases with permeate pressure and at large thickness region it decreases. From the Arrhenius plots of each component fluxes, the permeation activation energies were determined. Through an analysis of the permeation activation energies of each components, the desorption resistance as well as the effects of the thermodynamic factors on permeation was qualitatively characterized.