The chemical cleaning of polysulphone (PS) ultrafilters fouled during filtration of the glutamic fermentation broths was throughly investigated in this paper. The results demonstrated that the cleaning efficiency was strongly dependent on the cleaning mode and conditions, including agent concentration, cleaning temperature and time. As compared to the cleaning efficiency of two-step method, the combined simultaneous process (CSP) had merit. The cleaning kinetic equation was established and the active energy and rate constant of cleaning reactions were attained based on the first-order reaction and Arrhenius form. So, the cleaning ability and rate of different CSPs could be evaluated. Sodium dodecyl sulfate (SDS, C12H25OSO3Na) CSP achieved the strongest cleaning power and hydrogen peroxide (H2O2) CSP had the fastest cleaning rate. Also, the scanning electron microscopy (SEM) photographs of cleaned membrane surfaces were taken to directly observe the cleaning efficiency of different CSPs. (C) 2004 Elsevier B.V. All rights reserved.