The invention belongs to the atomic force microscope measurement technical field and provides a method for modifying the probe of an atomic force microscope by using magnetic nano-particles. With themethod adopted, the direct test of interaction between nano-particles and cells can be realized. According to the method, nano-scale magnetic particles and micro-scale carbon sphere particles are adopted; the V-shaped micro-cantilever and flat plate probe of the atomic force microscope are placed under the microscope; a particle mixed dispersion liquid is added dropwise, washing, drying and otherprocesses are performed, and therefore, a magnetic nano-particle-modified V-shaped cone-like tip probe can be obtained. The micro-scale carbon spheres are adopted as the carriers of the magnetic nano-particles, and therefore, experimental operation can be simplified, modification efficiency can be improved, a modification effect can be optimized, the direct test of the interaction between the nano-particles and the cells can be realized, and further experimental verification is provided for the uptake of the particles by the cells, adhesion forces between the particles and the cells, the survival ability of the cells and the like.