Abstract: A method for detecting biological markers involves preparing sample slices using a hard granular labeling material such as hard nano-gold granular material. The sample slices are fixed to sample patches. The sample is scanned using the atomic force microscope (AFM) in tapping mode to collect the height, amplitude and phase data of the hard granular material. The hard labeling material is mainly determined through changes in discrepancies in phase diagram color, while height and amplitude diagrams are used to provide auxiliary evidence of sample morphological features. Integrating these data with the state of the biological target object can thus determine the existence of a marked object.