Abstract: Ultrafiltration technology is widely applied in the treatment of ship's oily wastewater. In order to study the disposal testing characteristics of highly emulsified oily wastewater based on hydrophilic dialysis membranes, No.1000 cylinder oil and emulsifier is used to make highly emulsified oily wastewater, and a small oil/waster separating tester is created. The relationships between the temperature, consistency of original highly emulsified oily wastewater and dialysis membrane aperture are tested. Not only is the pollution resistance of the dialysis membrane tested on the basis of resolution MEPC.107(49), but the attenuation characteristic of the dialysis membrane is also tested after self-cleaning each time. All the tests show that for dialysis membranes with in the range 0.1 μm to 0.45 μm, the treatment capability will increase with the aperture; they all show a similar flow vs temperature curve, with the treatment capability first increasing and then decreasing with the increasing temperature; when the aperture of the dialysis membrane reaches 0.45 μm, the separation of highly emulsified oily wastewater is best achieved at 55-60℃. All the data and characteristics of this research will be helpful in the design and operation of highly emulsified oily wastewater disposal equipment.