Objective To study the toxicity of Quantum dots (QDs) and Quantum dots-Aβ-Ab (QDs-Aβ-Ab) probe to C57BL mice through histomorphological and behavioral comparisons, hepatic and renal function tests in order to evaluate the biocompatibility of QDs and QDs-Aβ-Ab probe.Methods Thirty normal C57BL mice were randomly divided into QDs, QDs-Aβ-Ab, and control groups.The responses were observed by behavioral comparisons, HE staining and nissl staining after injections of 5 μL QDs, QDs-Aβ-Ab probe or normil saline.Hepatic and renal functions were detected using automatic chemistry analyzer.Results Cell morphology, ultrastructure and nissl bodies in the hippocampal CA1 of the probe and the QDs groups were normal as the control group.Behavioral observation of seven days showed normal life behaviors and skin changes, walking disorders, excitatory linhibitory response or death did not occur in three groups.There were no significant differences in the contents of serum ALT, AST, BUN and CRE among the three groups.Conclusions The QDs and QDs-Aβ-Ab probes have no toxic effects and show a good biocompatibility in C57BL mice.