Uptake，metabolism and toxicity of iron cyanide complex in trees were investigated． Pre-rooted weeping willows(Solix babylonica L．)were exposed to hydroponic solution spiked with ferrocyanide at 24.0±1℃ for 192 h．Four different treatment concentrations offerrocyanide were used(52.99，105.98，211.95 and 317.93 mg CN L-1)．Cyanide in water， in tissues of aerial part of plants and in air was analyzed spectrophotometrically． Results from this study indicated less than 10.85％ reduction of the applied iron cyanide complex was detected in hydroponic solution in the presence of plants．Little amounts of cyanide were found in all parts of plant tissues， indicating the passage of ferrocyanide through the plants．Mass balance studies showed that iron cyanide complex moving into plants from hydroponic solution can be metabolized during transport． Phytotoxic efects were not found in all treatment groups，even at high doses of ferrocyanide within a 192-h exposure period．in conclusion，transport and metabolism of ferrocyanide in plants is most likely to happen and phytoremediation of this iron cyanide complex in field application may be possible．