Abstract: For robotic nanomanipulation based on an atomic force microscope(AFM),the working principle of interactive nano forces among the probe,substrate and particle is preliminarily analyzed.The decisive nano forces are pointed out to be Van der Waals force,repulsive contact force,nano frictional force,capillary force and nano electrostatic force,and their calculation formulas are also deduced. Simulation and experiments of force-distance curve are performed to verify the rationality of the analysis,which is helpful for accurate control of nanomanipulation.