Microfiltration of oil-in-water emulsions was studied with ceramic tube supported zirconium dioxide (ZrO2) dynamic membranes. Orthogonal experimental design was employed to optimize operating conditions, and factors such as temperature, pH, salt ion species of the emulsion and operating pressure were analyzed. Results show that the optimal microfiltration conditions are: emulsion concentration 0.5 g?L?1, flow rate 100 L?h?1 and operating pressure 0.14 MPa under 50℃. The steady permeate flux increases with the increase of pressure until 0.14 MPa, which remains constant afterwards. Moreover, the flux increases first and then decreases with the increase of temperature or pH. The flux of cationic salts is greater than that of anionic salts when adding salt ions in the emulsion. Higher cationic charges or lower anionic charges result in greater permeate flux. This fundamental research is useful for future studies of ceramic-based dynamic membranes in oily wastewater separation.