In this paper, we introduce our finding of the effects of C 60 nanoparticles (NP) infiltration on mechanical properties of cell and its membrane. Atomic force microscopy (AFM) is used to perform indentation on both normal and C 60 infiltrated red blood cells (RBC) to gain data of mechanical characteristics of the membrane. Our results show that the mechanical properties of human RBC membrane seem to be altered due to the presence of C 60 NPs . The resistance and ultimate strength of the C 60 infiltrated RBC membrane significantly decrease. We also explain the mechanism of how C 60 NPs infiltration changes the mechanical properties of the cell membrane by predicting the structural change of the lipid bilayer caused by the C 60 infiltration at molecular level and analyze the interactions among molecules in the lipid bilayer. The potential hazards and application of the change in mechanical characteristics of the RBCs membrane are also discussed. Nanotoxicity of C 60 NPs may be significant for some biological cells.