Amino-terminated PEG-phospholipid modified QDs (NH2-PEG-QDs), carboxyl-terminated PEG-phospholipid modified QDs (COOH-PEG-QDs) and methyl-terminated PEG-phospholipid modified QDs (CH3-PEG-QDs) were prepared by encapsulation of QDs into functional PEG-phospholipid micelles, and their nonspecifical binding to COS-7 cells were investigated. The results indicated that the number of QDs adsorbed on the COS-7 cells increased in the order of CH3-PEG-QDs, COOH-PEG-QDs, NH2-PEG-QDs. The interaction between functionalized QDs and cells was affected by particle concentration, surface charge of functionalized QD, incubation time, temperature and the serum in cell culture medium.