Epidermal growth factor receptor (EGFR) is widely spread in various types of cells and plays critical roles in cellular activities. Here we studied the EGFR distribution before and after activation by high-resolution mapping technique-topography and recognition imaging (TREC). The unbinding force between EGFR and its ligand, epidermal growth factor (EGF), was also measured by single-molecule force spectroscopy. Our results suggest that the majority of EGFRs are in the cluster state both in the resting and stimulated cells. This study provides qualitative information of the location, cluster state and binding kinetics of EGFRs in cell membranes at the molecular level.