Objective Stem cell therapy has been extensively used in clinical practice. However ,the methods available are unable to non‐invasively detect the distribution of cells in vivo. This study was aimed to establish a novel molecular imaging probe for stem cell labeling ,which would monitor cells via fluorescence imaging. Methods 1‐iodododecane was used to modify polyethyleneimine (PEI) to form amphiphilic macromolecules. These macromolecules encapsulated the hydrophobic quantum dots by self‐assembly to form imaging probes. Results Strong fluorescence signals of the probe occurred at 630 nm ,and the probe could be effectively endocyted by mesenchyme stem cells. In vivo imaging showed that significant optic signals occurred in probe‐labeled mesenchyme stem cells compared with the control cells (blank group:1.47e8 [p/s/cm2/sr]/[μW/cm2 ];test group:2.78e8 [p/s/cm2/sr]/[μW/cm2 ]). Conclusion The nanoprobes have good optic imaging effects ,and can be used to la‐bel cells.