Abstract An experimental investigation was carried out on microfiltration of oil-in-water emulsion using the coal-based carbon membrane prepared by carbonization of tubular precursor through extrusion method. Experimental results show that coal is a good precursor for preparation of the carbon membrane, and treatment of oil-in-water emulsion using the carbon membrane is feasible and effective with the oil rejection efficiency being over 98%. Based on the modified Hermia's model, membrane fouling mechanisms were analyzed and resistance controlling factors of permeate flow were discussed. Under the present operating conditions, there is a switch of fouling mechanisms from the standard pore fouling to the cake filtration at small apparent flow rate and trans-membrane pressure difference. When the values of two parameters are raised, the intermediate pore fouling becomes dominant after the early period of cake filtration.