Membrane that is generally used for separation process could be made using phase inversion technique. This research aims to create polyethersulfone (PES) asymmetric membranes via phase inversion technique using solvent and Trans Membrane Pressure (TMP) as variable. SEM analysis indicated that membranes had asymmetric structure that consits of two layers which denser skin layer on the top surface and the porous support on the bottom. PES/DMF membrane showed larger pore structure than PES/NMP. The permeability coefficients of both membranes were in the ultrafiltration range. The coefficient permeability (Lp) of PES/DMF membrane was 35.769 L/m2.hour, much greater compared to PES/NMP membrane which was 15.364 L/m2.hour.bar. Molecular Weight Cut-Off (MWCO) of PES/DMF membrane was 177 Kda, meanwhile PES/NMP was 186 Kda. Performances of the membranes were evaluated using dextrane as feed solution. PES/DMF membrane resulted in an higher flux and lower rejection than PES/NMP.