Abstract: The assessment of ecological safety was very important in the commercialize progress of transgenic fish. This paper described the concept of ecological safety, and took several species of transgenic fish as example to discuss the possible effects of transgenic fish on ecological safety from two aspects: the possible effects of transgenic fish on the biological diversity in contained facilities and the fitness changes in genetically engineered fish. Meanwhile, containment measures to prevent transgenic fish from escaping ware also reviewed in this paper.