Abstract In this study, error function was used to analyze the membrane fouling behavior (flux decay) for bovine serum album (BSA) solution in dead-end mode and for kaolin suspension in cross-flow mode under constant pressure. The results showed that the predictions of error function had good agreements with experimental data both in dead-end mode and cross-flow mode. Meanwhile, both higher concentration and higher TMP could accelerate the membrane fouling rate. In addition, the parameter k in error function decreased with the increase of concentration or TMP. Thus, smaller parameter k represented more serious membrane fouling.