A Moiré technique using a scanning probe microscope (SPM) is developed, in which the natural periodic structure of a crystal is used as an ideal spacing grating. Formation principle of the SPM moiré fringes is discussed. Moiré patterns formed on highly oriented pyrolytic graphite (HOPG) and mica are investigated experimentally with STM and AFM, respectively. The results demonstrate the feasibility of the SPM Moiré technique in studying deformation and defects of crystals at the nanometer scale.