In order to get a better understanding of the environmental behavior of 95Zr and to generate fundamental data for evaluation of its ecological risk, an experiment was conducted to study the distribution and the migration of 95Zr in a simulated fish/seawater/sediment system over a period of 20 days. The concentration of 95Zr in seawater decreased rapidly with time, and its half-life is only 0.2 day. Most of adsorbed 95Zr was found in upper 2.5 cm in sediment, and more than 99.3% of applied 95Zr was detected in upper 2.5 cm duringthe whole experimental period, which implied that the 95Zr in seawater could be adsorbed strongly by sediment and it could not readily migrate downwards with percolating water. After taken in by fish, it was accumulated in viscera, gill, and fin. The concentration of 95Zr was very low in meat, bone, liver and roe, which was only slightly greater than the detection limit. The dynamics of 95Zr concentrations in fish, seawater and sediment can be described with exponential function.