Atomic Force Microscope (AFM) is primarily a tool for characterizing surface topography, but there is also a strong interest in using AFM as a nano-manipulator to modify the sample surface or manipulate nano-structures. Nano-manipulation using the atomic force microscope has been extensively investigated for many years. It is greatly important to understand the mechanics of AFM-based nano-robotic manipulation for efficient and reliable handling of nano-particles. However, the micro/nano microscopes for this kind of application have not been developed completely. Moreover, real-time monitoring of the manipulation process is almost impossible. Since the same tool is used as either the imaging or manipulation tool at a given instant, imaging is almost not possible during nano-manipulation operation. As one approach to this problem, researchers scan the area, where the target particle exists, before and after the manipulation. Thus, by using some fixed reference features, the new relative position of the particle is obtained from the images. However, this imaging is offline, and the unexpected problems during nano-manipulation cannot be detected. This paper illustrates AFM cantilever force transducer modeling, which can convert the three-dimensional deflections measured by the detection system to corresponding three-dimensional force signals, so the real-time force information can be utilized during nano-manipulation for reliable handling of nano-particles.