Abstract: PDMS composite membranes were used to treat phenol wastewater. The composite membrane consists of a thin dense selective PDMS layer coated on a microporous PSf layer. The rate of organic transfer through the approximately 10μm PDMS layer membranes is much higher than that of a 0.5mm PDMS dense membrane in the reference. In our experiments，the recovery of phenol can be 99.9% and 96.9% from 0.939g/L and 8.977g/L wastewater，respectively. The overall mass transfer coefficient (OMTC) through thin PDMS layer is up to 3.92×10－7m/s calculated by mathematic model established in this paper，larger than 1.29×10－7m/s through PDMS tube. The pH value of NaOH solution has not effect on OMTC of phenol through thin PDMS layer，according with the mathematic model established in this paper. The transfer of phenol from electrolyte solutions containing NaCl has been studied. The OMTC of phenol containing NaCl is increased dramatically.