Abstract: Objective: to observe the effects of the surface treatment of the Ni-Ti shape memory alloy and the duration after the endosseous implantation on the nickel contents in the important organs and tissues of dogs. Methods: according to whether the Ni-Ti shapememory alloy dental implants for endosseous implantation in the thighs were treated with the aluminous bioceramics on the surface, the experimental dogs were divided into the composite group, which was observed for six months, and the Ni-Ti group, which was subdivided into two groups observed for three and six months respectively. Some other dogs were taken for the control. The nickel contents in liver, kidney, spleen and nasopharyngeal mucosa of all the dogs were measured, and the histopathological observations for those tissues were performed in due time. Results: the nickel contents tended to increase with the duration in the Ni-Ti group, but there were differences in the patterns of increase among the organs and tissues; the nickel contents of the composite group were significantly lower than those of the Ni-Ti group after six months, whereas they were still higher than those of the control group; no distinct abnormality was found in both groups by histopathological observation. Conclusion: there is an obvious restrain effect on the release of nickel by covering the surface of the Ni-Ti shape memory alloy with the aluminous bioceramics, but the treatment technology should be improved; the increase of the nickel contents in the organs and tissues is perhaps still within the range of biological safety because no distinct histopathological changes are found after the endosseous implantation of the Ni-Ti shape memory alloy.