Objective Study the effect of quantum dots (QDs) on macrophage cytochemistry and enzyme activity of mice in vitro. Methods To observe the macrophage biocompatibility with QDs and effect of QDs on PAS reaction, Feulgen reaction, ATPase,acid phosphatase (AcP), alkaline phosphatase(ALP), ANAE,SDH and LDH using inverted phase contrast microscope, fluorescence microscope, and cytochemistry methods were used. Results QDs hadn’t effect to macrophage structure in 3.125mg/L density of QDs, but its cytochemistry and cell enzyme activity had changed differently, that was PAS reaction, Feulgen reaction, AcP, ALP, ANAE and Mg2+ATP showed positive, and SDH and LDH showed negative. Feulgen reaction, ANAE, ALP and Mg2+ATP had statistical significance with the control group (P<0.05), PAS and AcP doesn’t have statistical significance with the control group(P>0.05). Conclusion In cell level, macrophage enzymes have chang