Abstract: Nested design was used to perform an experiment on the excretion of humans. The experiment examined the main relevant factors affecting excretion pollution coefficients. The results showed that the excretion coefficients of TN and TP were higher than those of COD_Cr, BOD₅, suggesting that the absorption rates of N and P were lower, and that when equivalent amounts of pollutants were ingested, there would be higher amounts of TN and TP than COD_Cr and BOD₅ in human excreta. Except for the COD_Cr excretion coefficient, the excretion coefficients among females were higher than those among males, with significant difference (P<0.05). This is possibly related to gender differences in weight, digestive ability and physical output. In addition, dietary patterns were also important factors affecting excretion coefficients, possibly associated with the levels and existing forms ofCOD_Cr, BOD₅, TP, TN in different kinds of food. Therefore, environmental problems induced by the change of dietary pattern should be given attention.