Abstract: Accumulations of lead and cadmium in gills, blood, liver, kidney, gut and muscle of goldfish, Carassius auratus var. exposed to various concentrations of either lead or cadmium were studied. The Langmuir isotherms were employed to describe the gill surface binding activity of lead or cadmium. The binding capacities(Bmax)and conditional equilibrium constants(log K)were 0.9424 mmol/kg dry wt and 7.80 for lead, 1.7662 μmol/kg dry wt and 6.38 for cadmium, respectively. The binding cooperativities(Hn)were very closed to unit(1.012 for lead and 1.175 for cadmium)indicating independent binding to the sites with one apparent affinity. There were positive correlations of metal contents between gills and blood and between blood and kidney or liver. There were more metal accumulated in kidney than in other organs.